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THE HISTOEY OF CEEATION.
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Development of a Calcareous Sponge (Olynthus)
THE
HISTORY OF CREATION :
on THE DEVELOPMENT OF THE EARTH AND ITS INHABITANTS BY THE ACTION OF NATURAL CAUSES.
A. POPULAR EXPOSITION OP
THE DOCTRINE OF EVOLUTION IN GENERAL, AND OF THAT OF
DARWIN, GOETHE, AND LAMARCK IN PARTICULAR,
FROM THE GERMAN OF
EEN ST HAE CKEL,
PfiOFESSOR IN THE UNIVERSITY OF JE.VxV.
THE TRANSLATION REVISED BY B. RAT LANKESTER, M,A., FELLOW OF EXETER COLLEGE, OXFORD.
IN TWO VOLUMES. VOL. I.
NEW YORK:
D. APPLETON AND COMPANY,
I, 3, AND 5 BOND STREET.
I 880.
A sense snbl'me Of sometliing far more deeply interfused, Whose dwelling is the light of setting suns. And the round ocean, and the living air, And the blue sky, and in the mind of man j A motion and a spirit that impels All thinking things, all objects of all thought. And rolls through all things.
In all things, in all natures, in the starq Of azure heaven, the nnenduring clouds, In flower and tree, in every pebbly stone That paves the brooks, the stationary rocks. The moving waters and the invisible air.
WORDSWOETH,
CONTENTS OF VOL. L
-VC^
CHAPTER I.
NATURE AND IMPORTANCE OF THE DOCTRINE OP FILIATION, -cr OR DESCENT.THEORY.
PAGE
General Importance and Essential Nature of the Theory of Descent as reformed by Darwin, — Its Special Importance to Biology (Zoology and Botany). — Its Special Importance to the History of the Natural Development of the Human Race. — The Theory of Descent as the Non-Miraculous History of Creation. — Idea of Creation. — Know, ledge and Belief. — History of Creation and History of Development. — The Connection between the History of Individual and Paloeonto- logical Development. — The Theory of Purposelessness, or the Science of Rudimentary Organs. — Useless and Superfluous Ar- rangements in Organisms. — Contrast between the two entirely Opposed Views of Nature : the Monistic (mechanical, causal) and the Dualistic (teleological, vital). — Proof of the former by the Theory of Descent. — Unity of Organic an4 Inorganic Nature, and the Identity of the Active Causes in both. — The Importance of the Theory of Descent to the Monistic Conception of all Nature ... 1
CHAPTER II.
SCIENTIFIC JUSTIFICATION OF THE THEORY OF DESCENT. HISTORY OP CREATION ACCORDING TO LINN.^US.
The Theory of Descent, or Doctrine of Filiation, as the Monistic Ex- planation of Organic Natural Phenomena. — Its Comparison with Newton's Theory of Gravitation. — Limits of Scientific Explanation and of Human Knowledge in general. — All Knowledge founded originally on Sensuous Experience, a posteriori. — Transition of d posteriori knowledge, by inheritance, into a priori knowledge. — Contrast between the Supernatural Hypotheses of the Creation ac-
V] CONTENTS.
PAGE
coi'ding to Linnaeus, Cuvier, Agassiz, and the Natural Theories of Development according to Lamarck, Goethe, and Darwin. — Con- nection of the former with the Monistic (mechanical), of the latter with the Dualistic Conception of the Universe, — Monism and Matei-ialism. — Scientific and Moral Materialism. — The History of Creation according to Moses. — Linnasus as the Founder of the Sys. teraatic Description of Natui-e and Distinction of Species. — Linnseus' Classification and Binary Nomenclature. — Meaning of Linnaeus' Idea of Species. — His History of Creation. — Linnteus' view of the Origin of Species 24
CHAPTER III.
THE HISTORY OF CREATION ACCORDING TO CUYIER
AND AGASSIZ.
General Theoretical Meaning of the Idea of Species. — Distinction be- tween the Theoretical and Practical Definition of the Idea of Species. — Cuvier's Definition of Species. — Merits of Cuvier as the Founder of Comparative Anatomy. — Distinction of the Four Principal Forms (types or branches) of the Animal Kingdom, by Cuvier and Bar. — Cuvier's Services to Palaeontology. — His Hypothesis of the Revo- lutions of our Globe, and the Epochs of Creation separated by them. — Unknown Supernatural Causes of the Revolutions, and the sub- sequent New Creations. — Agassiz's Teleological System of Nature. — His Conception of the Plan of Creation, and its six Categories (groups in classification). — Agassiz's Views of the Creation of Species. — Rude Conception of the Creator as a man -like being in Agassiz's Hypothesis of Creation. — Its internal Inconsistency and Contradictions with the important Palaeontological Laws dis- covered by Agassiz 47
CHAPTER IV.
THEORY OF DEVELOPMENT ACCORDING TO GOETHE
AND OKEN.
Scientific InsnflBciency of all Conceptions of a Creation of Individual Species — Necessity of the Counter Theories of Development. — Historical Survey of the most Important Theories of Development. — Aristotle. — His Doctrine of Spontaneous Generation. — The Meaning of Nature-philosophy. — Goethe. — His Merits as a Naturalist. — His Metamorphosis of Plants. — His Vertebral Theory of the Skull. — His Discovery of the Mid Jawbone in Man. — Goethe's Interest in the Dispute between Cuvier and Geoffroy
CONTENTS. Vll
PAGE
St. Hilaire. — Goethe's Discovery of the two Organic Formative Principles, of the Conservative Principle of Specification (by In- heritance), and of the Progressive Principle of Transformation (by Adaptation). — Goethe's Views of the Common Descent of all Ver- tebrate Animals, including Man. — Theory of Development according to Gottfried Keinhold Treviranus. — His Monistic Conception of Nature. — Oken. — His Nature-philosophy. — Oken's Theory of Protoplasm. — Oken's Theory of Infusoria (Cell Theory). — Oken's Theory of Development ... ... ... ... ... ... 72
CHAPTER V
THEORY OP DEVELOPMENT ACCOEDING TO KANT AND
LAMAECK.
Kant's Dualistic Biology. — His Conception of the Origin of Inorganic Nature by Mechanical Causes, of Organic Natui'e by Causes acting for a Definite Purpose. — Contradiction of this Conception with his leaning towards the Theory of Descent. — Kant's Genealogical Theory of Development. — Its Limitation by his Teleology. — Com- parison of Genealogical Biology with Comparative Philology. — Views in favour of the Theory of Descent entertained by Leopold Buch, Bar, Schleiden, Unger, Schaafhausen, Victor Cams, Biichner. — French Nature -philosophy. — Lamarck's Philosophie Zoologique. — Lamarck's Monistic (mechanical) System of Nature. — His Views of the Inter-action of the two Organic Formative Tendencies of Inheritance and Adaptation. — Lamarck's Conception of Man's Development from Ape-like Mammals. — Geoffrey St. Hilaire's, Naudin's, and Lecoq's Defence of the Theory of Descent. — English Nature -philosophy. — Views in favour of the Theory of Descent entertained by Erasmus Darwin, W. Herbert, Grant, Freke, Herbert Spencer, Hooker, Huxley. — The Double Merit of Charles Darwin ... 100
CHAPTER VI.
THEOEY OF DEVELOPMENT ACCOEDING TO LYELL
AND DAEWIN.
Charles Lyell's Principles of Geology. — His Natural History of the Earth's Development. — Origin of the Greatest Effects thi'ough the Multiphcation of the Smallest Causes. — Unlimited Extent of Geo- logical Periods. — Lyell's Eefutationof Cuvier's History of Creation. — The Establishment of the Uninterrupted Connection of Historical Development by Lyell and Darwin. — Biographical Notice of Charles Dai-win. — His Scientific Works. — Jlis Theory of Coral Eeefs. — De-
VIU CONTENTS.
PAGE
velopment of the Theory of Selection. — A Letter of Darwin's. — The Contemporaneous Appearance of Darwin's and Alfred Wallace's Theory of Selection. — Darwin's Study of Domestic Animals and Cultivated Plants. — Andreas Wagner's Notions as to the Special Creation of Cultivated Organisms for the good of Man. — The Tree of Knowledge in Paradise. — Comparison between Wild and Culti- vated Organisms. — Darwin's Study of Domestic Pigeons. — Import- ance of Pigeon Breeding. — Common Descent of all Eaces of 'jtigeons ••• ••• ••• ••• ..( ,,, ,,t ,,, ,,, i.^0
CHAPTER VII.
THE THEORY OF SELECTION (DARWINISM).
Darwinism (Theory of Selection) and Lamarckism (Theoiy of Descent). — The Process of Artificial Breeding. — Selection of the Different Individuals for After-breeding. — The Active Causes of Transmuta- tion.— Change connected with Food and Transmission by Inheritance connected with Propagation. — Mechanical Nature of these Two Physiological Functions. — The Process of Natural Breeding : Selection in the Struggle for Existence. — Malthus' Theory of Population. — The Proportion between the Numbers of Potential and Actual Individuals of every Species of Organisms. — General Straggle for Existence, or Competition to attain the Necessaries of Life. — Transforming Force of the Struggle for Existence. — Com- parison of Natural and Artificial Breeding — Selection in the Life of Man. — Military and Medical Selection ... ... ... ... 149
CHAPTER YIII.
TRANSMISSION BY INHERITANCE AND PROPAGATION.
Universality of Inheritance and Transmission by Inheritance. — Special Evidences of the same. — Human Beings with four, six, or seven Fingers and Toes. — Porcupine Men. — Transmission of Diseases, especially Diseases of the Mind. — Original Sin. — Hereditary Monarchies. — Hereditary Aristocracy. — Hereditary Talents and Mental Qualities. — Material Causes of Transmission by Inheritance. — Connection between Transmission by Inheritance and Propaga- tion. — Spontaneous Genei-ation and Propagation. — Nonsexual or Monogonous Propagation. — Propagation by Self -Division. — Monera and Amoeba. — Propagation by the formation of Buds, by the for- mation of Germ-Buds, by the foi-mation of Germ-Cells. — Sexual or Amphigonous Propagation. — Formation of Hermaphrodites. — Dis- tinction of Sexes, or Gonochorism. — Virginal Breeding, or Parthe-
CONTENTS. IX
PAGE
nogenesis. — Material Transmission of Peculiarities of both Parents to the Child by Sexual Propagation. — Difference between Trans- mission by Inheritance in Sexual and in Asexual Propagation ... 175
CHAPTER IX.
LAWS OF TRANSMISSION BY INHERITANCE. ADAPTATION AND NUTRITION.
Distinction between Conservative and Pr-ogressive Transmission by In- heritance.— Laws of Conservative Transmission : Transmission of Inherited Characters. — Uninten-upted or Continuous Transmission. — Interrupted or Latent Transmission. — Alternation of Generations. " — Relapse. — Degeneracy. — Sexual Transmission. — Secondary Sexual Characters. — Mixed or Amphigonoua Transmission. — Hybrids. — Abridged or Simplified Transmission. — Laws of Pro- gressive Inheritance : Transmission of Acquired Characters. — Adapted or Acquired Transmission. — Fixed or Established Trans- mission. — Homochronous Transmission (Identity in Epoch) . — nomotopic Transmission (Identity in Part). — Adaptation and Mutability. — Connection between Adaptation and Nutrition. — Dis- tinction between Indirect and Direct Adaptation ,., ,,. ... 203
CHAPTER X. LAWS OP ADAPTATION
Laws of Indirect or Potential Adaptation. — Individual Adaptation. — Monstrous or Sudden Adaptation. — Sexual Adaptation. — Laws of Direct or Actual Adaptation. — Universal Adaptation. — Cumulative Adaptation. — Cumulative Influence of External Conditions of Ex- istence and Cumulative Counter-Influence of the Organism. — Free Will. — Use and Non-use of Organs. — Practice and Habit. — Cor- relative Adaptation. — Correlation of Development. — Correlation of Organs. — Explanation of Indirect or Potential Adaptation by the Correlation of the Sexual Organs and of the other parts of the Body. — Divergent Adaptation. — Unlimited or Infinite Adaptation... 227
r
CHAPTER XI.
NATURAL SELECTION BY THE STRUGGLE FOR EXISTENCE. DIVISION OF LABOUR AND PROGRESS.
Interaction of the two Organic Formative Causes, Inheritance and Adaptation. — Natural and Artificial Selection. — Struggle for Ex- istence, or Competition for the Necessaries of Life. — Disproportion
CONTENTS.
PACE
between the Number of Possible or Potential, and tlie Number of Keal or Actual Individuals. — Complicated Correlations of all Neigh- bouring Organisms. — Mode of Action in NatmTil Selection. — Homo- chromic Selection as the Cause of Sympathetic Colourings. — Sexual Selection as the Cause of the Secondary Sexual Characters. — Law of Separation or Division of Labour (Polymorphism, Differ- entiation, Divergence of Chai-acters) . — Transition of Varieties into Species. — Idea of Species. — Hybridism. — Law of Progress or Per- fecting (Progressus, Teleosis) ... ... ... ... ... ... 252
CHAPTER XII.
LAWS OF DEVELOPMENT OF ORGANIC TRIBES AND OF INDIVIDUALS. PHYLOGENY AND ONTOGENY.
Laws of the Development of Mankind : Differentiation and Perfecting. — Mechanical Cause of these two Fundamental Laws. — Progress without Differentiation, and Differentiation without Progress. — • Origin of Rudimentary Organs by Non-use and Discontinuance of Habit. — Ontogenesis, or Individual Development of Organisms. — Its General Importance. — Ontogeny, or the Individual History of Development of Vertebrate Animals, including Man. — The Fructi- fication of the Egg. — Formation of the Three Germ Layers.— History of the Development of the Central Nervous System, of the Extremities, of the Branchial Arches, and of the Tail of Vertebrate Animals. — Causal Connection and Parallelism of Ontogenesis and Phylogenesis, that is, of the Development of Individuals and Tribes. — Causal Connection of the Parallelism of Phylogenesis and of Systematic Development. — Parallelism of the three Organic Series of Development 280
CHAPTER XIII.
THEORY OF THE DEVELOPMENT OF THE UNIVERSE AND OF THE EARTH. SPONTANEOUS GENERATION. THE CARBON THEORY. THE PLASTID THEORY.
History of the Development of the Earth. — Kant's Theory of the De- velopment of the Universe, or the Cosmological Gas Theory. — Development of Suns, Planets, and Moons. — First Origin of Water. — Comparison of Organisms and Anorgana. — Organic and Inorganic Substances. — Degrees of Density, or Conditions of Aggregation. — - Albuminous Combinations of Carbon. — Organic and Inorganic Forms. — Crystals and Formless Organisms without Organs. —
CONTENTS. XI
PAGE
Stereometrical Fundamental Forms of Crystals and of Organisms. — Organic and Inorganic Forces. — Yital Force. — Growth and Adapta- tion in Crystals and in Organisms, — Formative Tendencies of Crystals. — Unity of Organic and Inorganic Nature. — Spontaneous Generation, or Archigony. — Autogony and Plasmogony. — Origin of Monera by Spontaneous Generation. — Origin of Cells from Monera. — The Cell Theory. — The Plastid Theory. — Plastids, or Structm^al- Units. — Cytods and Cells. — Four Different Kinds of Plastids ... 316
CHAPTER Xiy.
MIGEATION AND DISTRIBUTION OF ORGANISMS. CHOROLOGY AND THE ICE-PERIOD OF THE EARTH.
Chorological Facts and Causes. — Origin of most Species in one Single Locality. — "Centres of Creation." — Distribution by Migration. — Active and Passive Migrations of Animals and Plants. — Means of Transport. — Transport of Germs by Water and by Wind. — Con- tinual Change of the Area of Distribution by Elevations and Depressions of the Groimd. — Chorological Importance of Geological Processes. — Influence of the Change of Climate. — Ice or Glacial Period. — Its Importance to Chorology. — Importance of Migrations for the Origin of New Species. — Isolation of Colonists. — Wagner's Law of Migration. — Connection between the Theory of Migration and the Theory of Selection. — Agreement of its Results with the Theoiy of Descent «•• ••• ..* ... 350
LIST OF ILLTJSTEATIOlSrS.
-*o^
PLATES.
Development of a Calcareotis Sponge (Olynthus) ...
I. — Life History of a Simplest Organism ...
II., III. — Germs or Embryos of Four Vertebrates ...
TAGS
... Frontispiece
To face page 184
„ 306
FIGUEES. 1. — Propagation of Moneron ... 2. — Propagation of Amoeba ... 3. — Egg of Mammal ... 4. — First Development of Mammal's Egg 5. — The Hmnan Egg Enlarged 6. — Development of Mammal's Egg 7. — Embryo of a Mammal or Bird ...
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AUTHOR'S PEEFACE TO THE ENGLISH EDITION,
-»♦*-
I AM desirous of prefacing the English edition of the " History of Creation " with a few remarks which may serve to explain the origin and object of this book. In the year 1866 I published, under the title " Generelle Morphologic," a somewhat comprehensive work, which constituted the first attempt to apply the general doctrine of development to the whole range of organic morphology (Anatomy and Biogenesis), and thus to make use of the vast march onwards which the genius of Charles Darwin has eflected in all biological science by his reform of the Descent Theory and its esta- blishment through the doctrine of selection. At the same time, in the " Generelle Morphologic," the first attempt was made to introduce the Descent Theory into the systematic classification of animals and plants, and to found a " natural system " on the basis of genealogy ; that is, to construct hj^pothetical pedigrees for the various species of organisms.
The " Generelle Morphologic " found but few readers, for which the voluminous and unpopular style of treatment, and its too extensive Greek terminology, may be chiefly to blame. But a proportionately large measure of approval has met
XIV PREFACE.
the " Naturliche Schopfimgsgeschiclite '* in Germany. This book took its origin in the shorthand notes of a course ot lectures which treated, before a mixed audience and in a popular form, the most important topics discussed in the " Generelle Morphologie." The notes were subsequently revised, and received considerable additions. The book appeared first in 1868, its fourth edition in 1873, and has been translated into several languages. I hope that it may also find sympathy in the fatherland of Darwin, the more so since it contains special morphological evidence in favour of many of the important doctrines with which this greatest naturalist of our century has enriched science. Proud as England may be to be called the fatherland of Newton, who, with his law of gravitation, brought inorganic nature under the dominion of natural laws of cause and effect, yet may she with even greater pride reckon Charles Darwin among her sons — he who solved the yet harder problem of bring- ing the complicated phenomena of organic nature under the sway of the same natural laws.
The reproach which is now oftenest made against the Descent Theory is that it is not securely founded, not suffi- ciently proven. Not only its distinct opponents maintain that there is a want of satisfactory proofs, but even faint-hearted and wavering adherents declare that Darwin's hypothesis is still wanting fundamental proof. Neither the former nor the latter estimate rightly the immeasurable weight which the great series of phenomena of comparative anatomy and onto- geny, palaeontology and taxonomy, chorology and cecology, cast into the scale in favour of the doctrine of filiation. Darwin's Theory of Selection, which completely explains the origin of species through the combined action of Inheritance
PREFACE. XV
and Adaptation in the struggle for existence, also appears to these persons not sufficient. They demand, over and above, that the descent of species from common ancestral forms shall be proved in a particular case ; that, in contradistinc- tion to the synthetic proofs adduced for the Descent Theory, the analytic proof of the genealogical continuity of the several species shall be brought forward.
This " analytical solution of the problem of the origin of species " I have myself endeavoured to afford in my recently published " Monograph of the Calcareous Sponges." For five consecutive years I have investigated this small but highly instructive group of animals in all its forms in the most careful manner, and I venture to maintain that the mono- graph, which is the result of those studies, is the most complete and accurate morphological analysis of an entire organic group which has up to this time been made. Provided with the whole of the material for study as yet brought together, and assisted by numerous contributions from all parts of the world, I was able to work over the whole group of organic forms known as the Calcareous Sponges in that greatest possible degree of fulness which appeared indispensable for the proof of the common origin of its species. This particular animal group is especially fitted for the analytical solution of the species problem, because it presents exceedingly simple conditions of organ- ization, because in it the morphological conditions possess a greatly superior, and the physiological conditions an inferior, import, and because all species of Calcispongise are remark- able for the fluidity and plasticity of their form. With a view to these facts, I made two journeys to the sea-coast (1869 to Norway, 1871 to Dalmatia), in order to study as
XVI PREFACE.
large a number of individuals as possible in their natural circumstances, and to collect specimens for comparison. Of many species, I compared several hundred individuals in the most careful way. I examined with the microscope and measured in the most accurate manner the details of form of all the species. As the final result of these exhaustive and almost endless examinations and measurements it appeared that "good species," in the ordinary dogmatic sense of the systematists, have no existence at all among the Calcareous Sponges ; that the most different forms are connected one with another by numberless gradational transition forms ; and that all the different species of Calca- reous Sponges are derived from a single exceedingly simple ancestral form, the Olynthus. A drawing of the Olynthus and its earliest stages of development (observe especially the highly important Gastrula) is given in the frontispiece of the present edition. Illustrations of the various structural details which establish the derivation of all Calcareous Sponges from the Olynthus, are given in the atlas of sixty plates which accompanies my monograph of the group. In the gastrula, moreover, is now also found the common ancestral form from which all the tribes of animals (the lowest group, that of the protozoa, alone being excepted) can without difficulty be derived. It is one of the most ancient and important ancestors of the human race !
If we take for the limitation of genus and species an average standard, derived from the actual practice of systematists, and apply this to the whole of the Calcareous Sponges at present known, we can distinguish about twenty-one genera, with one hundred and eleven species (as I have done in the second volume of the Monograph). I have, however, shown that we
PEEFACE. XVll
may draw up, in addition to this, another systematic arrange- ment (more nearly agreeing with the arrangement of the Calci- spongise hitherto in vogue) which gives thirty-nine genera and two hundred and eighty-nine species. A systematist who gives a more limited extension to the " ideal species " might arrange the same series of forms in forty-three genera and three hundred and eighty-one species, or even in one hundred and thirteen genera and five hundred and ninety species ; another systematist, on the other hand, who takes a wider limit for the abstract " species," would use in arrang- ing the same series of forms only three genera, with twenty- one species, or might even satisfy himself with one genus and seven species. The delimitation of species and genera appears to be so arbitrary a matter, on account of endless varieties and transitional forms in this group, that their number is entirely left to the subjective taste of the indi- vidual systematist. In truth, from the point of view of the theory of descent, it appears altogether an unimportant ques- tion as to whether we give a wider or a narrower signifi- cation to allied groups of forms — whether we choose, that is to say, to call them genera or species, varieties or sub-species. The main fact remains undeniable, viz., the common origin of all the species from one ancestral form. The many- shaped Calcareous Sponges furnish, in the very remarkable conditions of their varieties of aggregation (metrocormy), a body of evidence in favour of this view which could hardly be more convincing. Not unfrequently the case occurs of several different forms growing out from a single " stock " or " cormus " — forms which until now have been regarded b}^ systematists, not only as belonging to different species, but even to different genera. Fig. 10 in the frontispiece
XVlll PREFACE.
represents such a composite stock. This solid and tangible piece of evidence in favour of the common descent of different species ought, one would think, to satisfy the most determined sceptic !
In point of fact, I have a right to expect of my opponents that they shall carefully consider the " exact empirical proof" here brought forward for them, as they have so eagerly demanded. The opponents of the doctrine of filiation, who have too little power of weighing evidence, or possess too little knowledge to appreciate the overpowering weight of proof afforded by the synthetical argument (comparative anatomy, ontogeny, taxonomy, etc.), may yet be able to follow me along the path of analytical proof, and attempt to upset the conclusion as to the common origin of all species of all Calcareous Sponges which I have given in my Mono- graph. I must, however, repeat that this conclusion is based on the most minute investigation of an extraordinarily rich mass of material, — that it is securely established by thousands of the most careful microscopical observations, measurements, and comparisons of every single part, and that thousands of collected microscopic preparations render, at any moment, the most searching criticism of my results confirmatory of their correctness. One may hope, then, that opponents will endeavour to confront me on the ground of this "exact empiricism," instead of trying to damn my "nature-philosophical speculations." One may hope that they will endeavour to bring forward some evidence to show that the latter do not follow as the legitimate conse- quences of the former. May they, however, spare me the empty — though by even respectable naturalists oft-repeated — phrase, that the monistic nature-philosophy, as expounded
PEEFACE. XIX
in tlie "General Morphology," and in the "History of Creation," is wanting in actual proofs. The proofs are there. Of course those who turn their eyes away from them will not see them. Precisely that "exact" form of analytical proof which the opponents of the descent theory demand is to be found, by anybody who wishes to find it, in the " Monograph of the Calcareous Sponges."
Eknst Heinrich Haeckel.
Jena, June 2Wh, 1873.
NOTE
-♦o«-
Feeling sure that such a book as Professor Haeckel's " Schopfungsgeschichte " would do a great deal of good, if placed in the hands of the English reading public, and of commencing students of Natural History, I gladly under- took to revise for the publishers the present translation, which was made by a young lady. I have not attempted to escape a difficulty by ignoring the German names made use of by Professor Haeckel for classes, orders, and genera, but have adopted English equivalents. I do not submit these names as a maturely considered English nomenclature, they appear here simply as necessary parts of a close ren- dering of the German work. I do, however, hold that some such series of English terms is both possible and useful, and do not doubt — in spite of the pretended hostility of the genius of our language, and the curious sentimental objec- tion that English names are unscientific — that we shall before long make use of plain English in speaking of the various groups of plants and animals — much to the gain of the larger public, and without detriment to the latinized nomenclature established for the purposes of the professional student.
E. K. L.
Oxfordf October, 1874.
THE HISTOET OF CEEATION.
-♦o*-
CHAPTER L
NATURE AND IMPORTANCE OF THE DOCTRINE OF FILIATION, OR DESCENT-THEORY.
General Importance and Essential Nature of tlie Theory of Descent as re. formed by Darwin. — Its Special Importance to Biology (Zoology and Botany). — Its Special Importance to the History of the Natural Develop- ment of the Human Eace. — The Theory of Descent as the Non-Miraculous History of Creation. — Idea of Creation. — Knowledge and Belief. — His- tory of Creation and History of Development. — The Connection between the History of Individual and Palseontological Development. — The Theory of Purposelessness, or the Science of Rudimentary Organs. — Useless and Superfluous Arrangements in Organisms. — Contrast between the two entirely opposed Views of Nature : the Monistic (mechanical, causal) and the Dualistic (teleological, vital). — Proof of the former by the Theory of Descent. — Unity of Organic and Inorganic Nature, and the Identity of the Active Causes in both. — The Importance of the Theory of Descent to the Monistic Conception of all Nature.
The intellectual movement to which the impulse was given, thirteen years ago, by the English naturalist, Charles Darwin, in his celebrated work, " On the Origin of Species,"^ has, within this short period, assumed dimen- sions which cannot but excite the most universal interest. It is true the scientific theory set forth in that work, which is commonly called briefly Darwinism, is only a small fragment of a far more comprehensive doctrine — a part of the universal
2 THE HISTOHY OF CREATION.
Theory of Development, wliicli embraces in its vast range the whole domain of human knowleclofe.
But the manner in which Darwin has firmly established the latter by the former is so convincing, and the direction which has been given by the unavoidable conclusions of that theory to all our views of the universe, must appear to every thinking man of such deep significance, that its general importance cannot be over estimated. There is no doubt that this immense extension of our intellectual horizon must be looked upon as by far the most important, and rich in results, among all the numerous and grand advances which natural science has made in our day.
When our century, with justice, is called the age of natural science, when we look with pride upon the im- mensely important progress made in all its branches, we are generally in the habit of thinking more of immediate practical results, and less of the extension of our general knowledge of nature. We call to mind the complete reform, so infinitely rich in consequences to human intercourse, which has been effected by the development of machinery, by railways, steamships, telegraphs, and other inventions of physics. Or we think of the enormous influence which chemistry has brought to bear upon medicine, agriculture, and upon all arts and trades.
But "much as we may value this influence of modem science upon practical life, still it must, estimated from a hio-her and more general point of view, stand most assuredly below the enormous influence which the theoretical progress of modern science will have on the entire range of human knowledge, on our conception of the universe, and on the perfecting of man's culture.
IMPORTANCE OF DARWINISM. 3
Think of the immense revolutions in all our theoretical views which we owe to the general application of the microscope. Think of the cell theory, which explains the apparent unity of the human organism as the combined result of the union of a mass of elementary vital units. Or consider the immense extension of our theoretical horizon which we owe to spectral analysis and to the mechanical theory of heat. But among all these wonderful theoretical advances, the theory wrought out by Darwin occupies by far the highest rank.
Every one of my readers has heard of the name of Dar- win. But most persons have probably only an imperfect idea of the real value of his theory. If a reader estimates as of equal value all that has been written upon Darwin's memorable work since its appearance, the value of the theory will appear very doubtful to him, supposing that he has not been engaged in the organic natural sciences, and has not penetrated into the inner secrets of zoology and botany. The criticisms of it are so full of contradic- tions, and for the most part so defective, that we ought not to be at all astonished that even now, after the lapse of thirteen years since the appearance of Darwin's work, it has not gained half that importance which is justly due to it, and which sooner or later it certainly will attain.
Most of the innumerable writings which have been pub- lished during these years, both for and against Darwinism, are the productions of persons who are entirely wanting in the necessary amount of biological, and especially of zoolo- gical, knowledge. Although almost all of the more celebrated naturalists of the present day are adherents of the theory, yet only a few of them have endeavoured to procure its
4 THE HISTOEY OF CREATION.
acceptance and recognition in larger circles. Hence the odd contradictions and the strange opinions which may still be heard everywhere about Darwinism. This is the reason which induces me to make Darwin's theory, and those further doctrines which are connected with it, the subject of these pages, which, I hope, will be generally intelligible. I hold it to be the duty of naturalists, not merely to meditate upon improvements and discoveries in the narrow circle to which their speciality confines them, not merely to pore over their one study with love and care, but also to seek to make the important general results of it fruitful to the mass, and to assist in spreading the knowledge of physical science among the people. The highest triumph of the human mind, the true knowledge of the most general laws of nature, ought not to remain the private possession of a privileged class of savans, but ought to become the common property of all mankind.
The theory which, through Darwin, has been placed at the head of all our knowledge of nature, is usually called the Doctrine of Filiation, or the Theory of Descent. Others term it the Transmutation Theory. Both designations are correct. For this doctrine affirms, that all organisons (viz. all species of animals, all species of plants, which have ever existed or still exist on the earth) are derived from one single, or from a few simple original forons, and that they have developed theonselves from these in the natural course of a gradual change. Although this theory of development had already been brought forward and defended by several great natm-al- ists, and especially by Lamarck and Goethe, in the beginning of our centiu-y, still it was through Darwin, thirteen years ago, that it received its complete demonstration and causal
OEGANA AND ANOEGAXA. 5
foundation ; and this is the reason why now it is commonly and exclusively (though not quite correctly) designated as Darwin's Theory,
The great and really inestimable value of the Theory of Descent appears in a different light, accordingly as we merely consider its more immediate connection with organic natural science, or its larger influence upon the whole range of man's knowledge of the universe. Organic natural science, or Biology, which as Zoology treats of animals, as Botany of plants, is completely reformed and founded anew by the Theory of Descent. For by this theory we are made acquainted with the active causes of organic forms, while up to the present time Zoology and Botany have simply been occupied with the facts of these forms. We may therefore also term the theory of descent a onechanical explanation of organic forms, or the science of the true causes of Organic Nature.
As I cannot take for granted that my readers are all
familiar with the terms " organic and inorganic nature,"
and as the contrast of both these natural bodies will, in
future, occupy much of our attention, I must say a few
words in explanation of them. We designate as Organisms,
or Organic bodies, all living creatures or animated bodies;
therefore all plants and animals, man included ; for in them
we can almost always prove a combination of various parts
(instruments or organs) which work together for the purpose
of producing the phenomena of life. Such a combination
we do not find in Anorgana, or inorganic natural bodies —
the so-called dead or inanimate bodies, such as minerals or
stones, water, the atmospheric air, etc. Organisms always
contain albuminous combinations of carbon in a semi-fluid 2
6 THE HISTORY OF CREATION.
condition of aggregation, which are always wanting in the Anorgana. Upon this important distinction rests the divi- sion of all natural history into two great and principal parts — Biology, or the science of Organisms (Zoology and Botany), and Anorganology, or the science of Anorgana (Mineralogy, Geology, Meteorology, etc.).
The great value of the Theory of Descent in regard to Biology consists, as I have already remarked, in its explain- ing to ns the origin of organic forms in a mechanical way, and pointing out their active causes. But however highly and justly this service of the Theory of Descent may be valued, yet it is almost eclipsed by the immense importance which a single necessary inference from it claims for itself alone. This necessary and unavoidable inference is the theory of the animal descent of the human race.
The determination of the position of man in nature, and of his relations to the totality of things — this question of all questions for mankind, as Huxley justly calls it — ^is finally solved by the knowledge that man is descended from animals. In consequence of Darwin's reformed Theory of Descent, we are now in a position to establish scientifically the groundwork of a non-miixiculous history of the de- velopment of the human race. All those who have defended Darwin's theory, as well as all its thoughtful opponents, have acknowledged that, as a matter of necessity, it follows from his theory that the human race, in the fii^st place, must be traced to ape-like mammals, and further back to the lower vertebrate animals.
It is true Darwin himself did not express at first this most important of all the inferences from his theory. In nis work, " On the Origin of Species," not a word is found
OEIGIN OF MAN. 7
about the animal descent of man. The courageous but cautious naturalist was at that time purposely silent on the subject, for he anticipated that this most important of all the conclusions of the Theory of Descent was at the same time the greatest obstacle to its being generally accepted and acknowledged. Certain it is that Darwin's book would have created, from the beginning, even much more opposi- tion and offence, if this most important inference had at once been clearly expressed. It was not till twelve years later, in his work on " The Descent of Man, and Selection in Eelation to Sex," that Darwin openly acknowledged that far-reaching conclusion, and expressly declared his entire agreement with those naturalists who had, in the mean- time, themselves formed that conclusion. Manifestly the effect of this conclusion is immense, and no science will be able to escape from the consequences. Anthropology, or the science of man, and consequently all philosophy, are thereby thoroughly reformed in all their various branches.
It will be a later task in these pages to discuss this special point. I shall not treat of the theory of the animal descent of man till I have spoken of Darwin's theory, and its general foundation and importance. To express it in one word, that most important, but (to most men) at first repulsive, conclusion is nothing more than a special deduc- tion, which we must draw from the general inductive law of the descent theory (now firmly established), according to the stern commands of inexorable logic.
Perhaps nothing will make the full meaning of the theory of descent clearer than calling it " the non-miraculous history of creation." I have therefore chosen that name for this work. It is, however, correct only in a certain
8 THE HISTORY OF CREATION.
sense, and it must be borne in mind that, strictly speaking, the expression "non-miraculous history of creation" contains a " contradictio in adjecto."
In order to understand this, let us for a moment examine somewhat more closely what we understand by creation. If we understand the creation to mean the coming into existence of a body by a creative power or force, we may then either think of the coming into existence of its sub- stance (corporeal matter), or of the coming into existence of its form (the corporeal form).
Creation in the former sense, as the coming into existence of matter, does not concern us here at all. This process, if indeed it ever took place, is completely beyond human com- prehension, and can therefore never become a subject of scientific inquiry. Natural science teaches that matter is eternal and imperishable, for experience has never shown us that even the smallest particle of matter has come into existence or passed away. Where a natural body seems to disappear, as for example by burning, decaying, evaporation, etc., it merely changes its form, its physical composition or chemical combination. In like manner the coming into existence of a natural body, for example, of a crystal, a fungus, an infusorium, depends merely upon the different particles, which had before existed in a certain form or com- bination, assuming a new form or combination in conse- quence of changed conditions of existence. But never yet has an instance been observed of even the smallest particle of matter having vanished, or even of an atom being added to the already existing mass. Hence a naturalist can no more imagine the coming into existence of matter, than he can imagine its disappearance, and he therefore looks upon
SCIENCE AND FAITH. 9
the existing quantity of matter in the universe as a given fact. If any person feels the necessity of conceiving the coming into existence of this matter as the work of a super- natural creative power, of the creative force of something outside of matter, we have nothing to say against it. But we must remark, that thereby not even the smallest advan- tage is gained for a scientific knowledge of nature. Such a conception of an immaterial force, which at the first creates matter, is an article of faith which has nothing whatever to do with human science. Where faith com')nences, science ends. Both these arts of the human mind must be strictly kept apart from each other. Faith has its origin in the poetic imagination ; knowledge, on the other hand, originates in the reasoning intelligence of man. Science has to pluck the blessed fruits from the tree of knowledge, unconcerned whether these conquests trench upon the poetical imagin- ings of faith or not.
If, therefore, science makes the " history of creation " its highest, most difficult, and most comprehensive problem, it must accept as its idea of creation the second explanation of the word, viz. the coming into being of the form of natural bodies. In this way geology, which tries to in- vestigate the origin of the inorganic surface of the earth as it now appears, and the manifold historical changes in the form of the solid crust of the earth, may be called the history of the creation of the earth. In like manner, the history of the development of animals and plants, which investigates the origin of living forms, and the manifold historical changes in animal and vegetable forms, may be termed the history of the creation of organisms. As, how- ever, in the idea of creation, although used in this sense, the
lO THE HISTORY OF CEEATLON.
unscientific idea of a creator existing outside of matter, and changing it, may easily creep in, it will perhaps be better in future to substitute for it the more accurate term, develop- vient
The great value which the History of Development pos- sesses for the scientific understanding of animal and vege- table forms, has now been generally acknowledged for many years, and without it it would be impossible to make any sure progress in organic morphology, or the theory of forms. But by the history of development, only one part of this science has generally been understood, namely, that of organic individuals, usually called Embryology, but more correctly and comprehensively, Ontogeny. But, besides this, there is another history of development of organic species, genera, and tribes (phyla), which has the most important relations to the formet.
The subject of this is furnished to us by the science of petrifactions, or palaeontology, which shows us that each tribe of animals and plants, during different periods of the earth's history, has been represented by a series of entirely different genera and species. Thus, for example, the tribe of vertebrated animals was represented by classes of fish, amphibious animals, reptiles, birds, and mammals, and each of these groups, at different periods, by quite different kinds. This palseontological history of the development of organ- isms, which we may term Phylogeny, stands in the most important and remarkable relation to the other branch of oi^ganic history of development, I mean that of individuals, or Ontogeny. On the whole, the one runs parallel to the other. In fact, the history of individual development, or Ontogeny, is a short and quick recapitulation of palaeonto-
BIOLOGY EEFOKMED. II
logical development, or Phylogeny, dependent on the laws of Inheritance and Adaptation.
As I shall have, later, to explain this most interesting and important coincidence more fully, I shall not dwell further upon it here, and merely call attention to the fact that it can only be explained and its causes understood by the Theory of Descent, while without that theory it remains completely incomprehensible and inexplicable. The Theory of Descent in the same way shows us why individual animals and plants must develop at all, and why they do not come into life at once in a perfect and developed state. No super- natural history of creation can in any way explain to us the great mystery of organic development. To this most weighty question, as well as to all other biological ques- tions, the Theory of Descent gives us perfectly satisfactory answers — and always answers which refer to purely me- chanical causes, and point to purely physico-chemical forces as the causes of phenomena which we were formerly accus- tomed to ascribe to the direct action of supernatural, creative forces. Hence, by our theory the mystic veil of the miraculous and supernatural, which has hitherto been allowed to hide the complicated phenomena of this branch of natural knowledge, is removed. All the departments of Botany and Zoology, and especially the most important por- tion of the latter, Anthropology, become reasonable. The dimming mirage of mythological fiction can no longer exist in the clear sunlight of scientific knowledge.
Of special interest among general biological phenomena are those which are quite irreconcilable with the usual supposition, that every organism is the product of a creative power, acting for a definite object. Nothing in this respect
12 THE HISTOEY OF CREATION.
caused the earlier naturalists greater difficulty tlian tlie explanation of the so-called " rudimentary organs" — those parts in animal and vegetable bodies which really have no function, which have no physiological importance, and yet exist in form. These parts deserve the most careful atten- tion, aithouo^h most unscientific men know little or nothino^ about them. Almost every organism, almost every animal and plant possesses, besides the obviously useful arrange- ments of its organization, other arrangements the purpose of which it is utterly impossible to make out.
Examples of this are found everywhere. In the embryos of many ruminating animals — among others, in our common cattle — fore-teeth, or incisors, are placed in the mid-bone of the upper jaw, which never fully develop, and therefore serve no purpose. The embryos of many whales — ^which afterwards possess the well-known whalebone instead of teeth, yet have before they are born, and while they take no nourishment, teeth in their jaws, which set of teeth never comes into use. Moreover, most of the higher animals pos- sess muscles which are never employed ; even man has such rudimentary muscles. Most of us are incapable of moving our ears as we wish, although the muscles for this move- ment exist, and although individual persons who have taken the trouble to exercise these muscles do succeed in moving their ears. It is still possible, by special exercise, by the persevering influence of the will upon the nervous system, to reanimate the almost extinct activity in the existing but imperfect organs, which are on the road to complete disappearance. On the other hand, we can no longer do this with another set of small rudimentary muscles, which still exist in the cartilage of the outer ear.
RUDIMENTARY ORGANS. 13
but wliicli are always perfectly inactive. Our long-eared ancestors of the tertiary period — apes, semi-apes, and pouched animals, like most other mammals, moved their large ear-flaps freely and actively; their muscles were much more strongly developed and of great importance. In a similar way, many varieties of dogs and rabbits, under the influence of civilized life, have left off " pricking up " their ears, and thereby have acquired imperfect amricular muscles and loose-hanging ears, although their wild ancestors moved their stiff" ears in many ways.
Man has also these rudimentary organs on other parts of his body ; they are of no importance to life, and never per- form any function. One of the most remarkable, although the smallest organ of this kind, is the little crescent-like fold, the so-called "plica semilunaris," which we have in the inner corner of the eye, near the root of the nose. This in- significant fold of skin, which is quite useless to our eye, is the imperfect remnant of a third inner eyelid which, besides the upper and under eyelid, is highly developed in other mammals, and in birds and reptiles. Even our very remote ancestors of the Silurian period, the Primitive Fishes, seem to have possessed this third eyelid, the so-called nicti- tating membrane. For many of their nearest kin, who still exist in our day but little changed in form, viz. many sharks, possess a very strong nictitating membrane, which they can draw right across the whole eyeball, from the inner corner of the eye.
Eyes which do not see form the most striking example of rudimentary organs. These are found in very many animals, which live in the dark, as in caves or underground. Their eyes often exist in a well-developed condition, but they are
14 THE HISTORY OF CEEATION.
covered by membrane, so that no ray of light can enter, and they can never see. Such eyes, without the function of sight, are found in several species of moles and mice which live underground, in serpents and lizards, in amphibious animals (Proteus, Csecilia), and in fishes ; also in numerous invertebrate animals, which pass their lives in the dark, as do many beetles, crabs, snails, worms, etc.
An abundance of the most interesting examples of rudi- mentary organs is furnished by Comparative Osteology, or the study of the skeletons of vertebrate animals, one of the most attractive branches of Comparative Anatomy. In most of the vertebrate animals we find two pairs of limbs on the body, a pair of fore-legs and a pair of hind-legs. Very often, however, one or the other pair is imperfect; it is seldom that both are, as in the case of serpents and some varieties of eel-like fish. But some serpents, viz. the giant serpents (Boa, Python), have stiR in the hinder portion of the body some useless little bones, which are the remains of lost hind-legs.
In like manner the mammals of the whale tribe (Cetacea), which have only fore-legs fully developed (breast-fins j, have further back in their body another pair of utterly superfluous bones, which are remnants of undeveloped hind-legs. The same thing occurs in many genuine fishes, in which the hind-leo^s have in like manner been lost.
Again, in our slow- worm (Anguis), and in some other lizards, no fore-legs exist, although they have a perfect shoulder apparatus within their bodies, which should serve as a means of afiixing the legs. Moreover, in various ver- tebrate animals, the single bones of both pairs of legs are found in all the difierent stages of imperfection, and often the decfenerate bones and those muscles belonging to them
RUDIMENTARY ORGANS. 1 5
are partially preserved, without their being able in any way to perform any function. The instrument is still there, but it can no longer play.
Moreover, we can, almost as generally, find rudimentary organs in the blossoms of plants, inasmuch as one part or another of the male organs of propagation — the stamen and anther, or of the female organs of propagation — the style, germ, etc. — is more or Jess imperfect or abortive. Among these we can trace, in various closely connected species of plants, the organ in all stages of degeneration. Thus, for example, the great natural family of lip-blossomed plants (Labiat?e), to which the balm, peppermint, marjoram, ground- ivy, thyme, etc., belong, are distinguished by the fact that their mouth-like, two-lipped flower contains two long and two short stamens. But in many exceptional plants of this family, e, g. in different species of sage, and in the rosemary, only one pair of stamens is developed; the other pair is more or less imperfect, or has quite disappeared. Sometimes stamens exist, but without the anthers, so that they are utterly useless. Less frequently the rudiment or imperfect remnant of a fifth stamen is found, physiologically (for the functions of life) quite useless, but morphologically (for the knowledge of the form and of the natural relationship) a most valuable organ. In my "General Morphology of Organisms," * in the chapter on " Purposelessness, or Dysteleology," I have given a great number of other examples (Gen, Morph. ii. 226).
No biological phenomenon has perhaps ever placed zoologists or botanists in greater embarrassment than these rudimentary or abortive organs. They are instruments without employment, parts of the body which exist without
1 6 THE HISTOEY OF CREATION.
performing any service — adapted for a purpose, but without in reality fulfilling that purpose. When we consider the attempts which the earlier naturalists have made in order to explain this mystery, we can scarcely help smiling at the strange ideas to which they were led. Being unable to find a true explanation, they came, for example, to the conclu- sion that the Creator had placed these organs there "for the sake of symmetry," or they believed that it had appeared unwise and unsuitable to the Creator (seeing that their nearest kin did possess such organs) that these organs should be completely wanting in creatures, where they are incapable of performing a function, and where it cannot be otherwise from the special mode of life. In compensation for the non-existing function, he had at least furnished them with the outward but empty form ; nearly in the same manner as civil ofiicers, in uniform, are furnished with an innocent sword, which is never dra^yn from the scabbard. I scarcely believe, however, that any of my readers will be content with such an explanation.
Now, it is precisely this widely spread and mysterious phenomenon of rudimentary organs, in regard to which all other attempts at explanation fail, which is perfectly ex- plained, and indeed in the simplest and clearest way, by Darwin's Theory of Inheritance and Adaptation. We can trace the important laws of inheritance and adaptation in the domestic animals which we breed, and the plants which we cultivate ; and a series of such laws of inheritance have already been established. Without going further into this at present, I will only remark that some of them perfectly explain, in a mechanical way, the coming into existence of rudimentary organs, so that we must look u})on the appear-
RUDIMENTARY ORGANS. I 7
ance of such structures as an entirely natural process, arising from the disuse of the organs.
By adaptation to special conditions of life, the formerly active and really working organs have gradually ceased to be used or employed. In consequence of their not being exercised they have become more and more imperfect, but in spite of this have always been handed down from one generation to another by inheritance, until at last they vanish partially or entirely. Now, if we admit that all the vertebrate animals mentioned above are derived from one common ancestor, possessing two seeing eyes and two well developed pairs of legs, the different stages of suppres- sion and degeneration of these organs are easily accounted for in such of the descendants as could no longer use them. In like manner the various stages of suppression of the stamens, originally existing to the number of five (in the flower-bud), among the Labiatge is explained, if we admit tliat all the plants of this family sprung from one common ancestor, provided with ^ve stamens.
I have here spoken somewhat fully of the phenomena of rudimentary organs, because they are of the utmost general importance, and because they lead us to the great, general, and fundamental questions in philosophy and natural science, for the solution of which the Theory of Descent has now become the indispensable guide. As soon, in fact, as, according to this theory, we acknowledge the exclusive activity of physico-chemical causes in living (organic) bodies, as well as in so-called inanimate (inorganic) nature, we concede exclusive dominion to that view of the uni- verse, which we may designate as the mechanical, and which is opposed to the teleological conception. If we
1 8 THE HISTORY OF CREATION.
compare all the ideas of tlie universe prevalent among different nations at different times, we can divide them all into two sharply contrasted groups — a causal or rtie- chanical, and a teleological or vitalistic. The latter has pre- vailed generally in Biology until now, and accordingly the animal and vegetable kingdoms have been considered as the products of a creative power, acting for a definite pur- pose. In the contemplation of every organism the unavoid- able conviction seemed to press itself upon us, that such a wonderful machine, so complicated an apparatus for motion as exists in the organism, could only be produced by a power analogous to, but infinitely more perfect than, the power of man in the construction of his machines.
However sublime the former idea of a Creator, and his creative power, may have been ; however much it may be attempted to divest it of all human analogy, yet in the end this analogy still remains unavoidable and necessary in the teleological conception of natui^e. In reality the Creator must himself be conceived of as an organism, that is, as a being who, analogous to man, even though in an infinitely more perfect form, reflects on his constructive power, lays down a plan of his mechanisms, and then, by the application of suitable materials, makes them answer their purpose. Such conceptions necessarily suffer from the fundamental error of anthropomorphism, or man-likening. In such a view, however exalted the Creator may be imagined, we assigTi to him the human attributes of designing a plan, and therefrom suitably constructing the organism. This is, in fact, quite clearly expressed in that view which is most sharply opposed to Darwin's theory, and which has found among naturalists its most disting-uished representative in
THE TELEOLOGICAL VIEW. 1 9
Agassiz. His celebrated work, " An Essay on Classifica- tion," ^ which is entirely opposed to Darwin's, and appeared almost at the same time, has elaborated quite consistently, and to the utmost extent, these anthropomorphic conceptions of the Creator.
I maintain with regard to the much-talked-of "purpose in nature," that it really has no existence but for those persons who observe phenomena in animals and plants in the most superficial manner. Without going more deeply into the matter, we can see at once that the rudimentary organs are a formidable obstacle to this theory. And, indeed, every one who makes a really close study of the organization and mode of life of the various animals and plants, and becomes familiar with the reciprocity or inter-action of the phenomena of life, and the so-called " economy of nature," must necessarily come to the conclusion that this *' purposiveness " no more exists than the much-talked-of " beneficence " of the Creator. These optimistic views have, unfortunately, as little real foundation as the favourite phrase, the " moral order of the universe," which is illustrated in an ironical way by the history of all nations. The dominion of the " moral " popes, and their pious inquisition, in the mediaeval times, is not less significant of this than the present prevailing militarism, with its " moral " apparatus of needle-guns and other refined instruments of murder.
If we contemplate the common life and the mutual rela- tions between plants and animals (man included), we shall find everywhere, and at all times, the very opposite of that kindly and peaceful social life which the goodness of the Creator ought to have prepared for his creatures — we shall
20 THE HISTORY OF CREATION.
ratliGr find everywliere a pitiless, most embittered Struggle of All against All. Nowhere in nature, no matter where we turn our eyes, does that idyllic peace, celebrated by the poets, exist ; we find everywhere a struggle and a striving to annihilate neighbours and competitors. Passion and selfishness — conscious or unconscious — is everywhere the motive force of life. The well-known words of the German poet —
** Die Welt ist vollkommen iiberall Wo der Menscli nicht hinkommt mit seiner Qual." *
are beautiful, but, unfortunately, not true. Man in this re- spect certainly forms no exception to the rest of the animal world. The remarks which we shall have to make on the theory of " Struggle for Existence " will sufficiently justify this assertion. It is, in fact, Darwin who has placed this important point, in its high and general significance, very clearly before our eyes, and the chapter in his theory which he himself calls " Struggle for Existence " is one of the most important parts of it.
Wliilst, then, we emphatically oppose the vital or teleological view of animate nature which presents animal and vegetable forms as the productions of a kind Creator, acting for a definite purpose, or of a creative, natural force acting for a definite purpose, we must, on the other hand, decidedly adopt that view of the universe which is called the ^mechanical or causal. It may also be called the monistic, or single-principle theory, as opposed to the tivo- folcl principle, or dualistic theory, which is necessarily implied in the teleological conception of the universe. The
* The world is perfect save where Man Comes in with his stiife.
PHYSICS AND BIOLOGY. 21
mechanical view of nature has for many years been so firmly established in certain domains of natural science, that it is here unnecessary to say much about it. It no longer occurs to physicists, chemists, mineralogists, or astronomers, to seek to find in the phenomena which continually appear before them in their scientific domain the action of a Creator acting for a definite purpose. They universally, and with- out hesitation, look upon the phenomena which appear in their different departments of study as the necessary and invariable effects of physical and chemical forces which are inherent in matter. Thus far their view is purely material- istic, in a certain sense of that " word of many meanings."
When a physicist traces the phenomena of motion in elec- tricity or magnetism, the fall of a heavy body, or the undulations in the waves of light, he never, in the whole course of his research, thinks of looking for the interference of a supernatural power. In this respect. Biology, as the science of so-called " animated " natural bodies, was formerly placed in sharp opposition to the above-mentioned inorganic natural sciences (Anorganology). It is true modern Physi- ology, the science of the phenomena of motion in animals and plants, has completely adopted the mechanical view ; but Morphology, the science of the forms of animals and plants, has not been affected at all by it. Morphologists, in spite of the position of physiology, have continued, as before, in oppo- sition to the mechanical view of functions, to look upon the forms of animals and plants as something which cannot be at all explained mechanically, but which must owe its origin necessarily to a higher, supernatural creative power, acting for a definite purpose.
In this general view it is quite indifferent whether the
22 THE HISTOEY OF CREATION.
creative power be worshipped as a personal god, or whether it be termed the power of life (vis vitalis), or final cause (causa finalis). In any case, to express it in one word, its supporters have recourse to a miracle for an explanation. They throw themselves into the arms of a poetic faith, which as such can have no value in the domain of scientific knowledge.
All that was done before Darwin, to establish a natural mechanical conception of the origin of animals and plants, has been in vain, and until his time no theory gained a general recognition. Darwin's theory first succeeded in doino: this, and thus has rendered an immense service. For the idea of the unity of organic and inorganic nature is now firmly established; and that branch of natural science which had longest and most obstinately opposed mechanical conception and explanation, viz. the science of the structure of animate forms, is launched on to identically the same road towards perfection as that along which all the rest of the natural sciences are travelling. The unity of all natural phenomena is by Darwin's theory finally established.
This unity of all nature, the animating of all matter, the inseparability of mental power and corporeal substance, Goethe has asserted in the words : " Matter can never exist and be active without mind, nor can mind without matter." These first principles of the mechanical conception of the universe have been taught by the great monistic philosophers of all ages. Even Democritus of Abdera, the immortal founder of the Atomic theory, clearly expressed them about 500 years before Christ; but the great Dominican friar, Giordano Bruno, did so even more explicitly. For this he was burnt at the stake, by the Christian inquisition in
ALL NATUEE IS ANIMATE. 23
Rome, on the ITtli of Feb., 1600, on the same day on which, 36 years before, Galileo, his great fellow-countryman and fellow-worker, was born. Such men, who live and die for a great idea, are usually stigmatized as " materialists " ; but their opponents, whose arguments were torture and the stake, are praised as " spiritualists."
By the Theory of Descent we are for the first time enabled to conceive of the unity of nature in such a manner that a mechanico-causal explanation of even the most intricate organic phenomena, for example, the origin and structure of the organs of sense, is no more difficult (in a general way) than is the mechanical explanation of any physical process ; as, for example, earthquakes, the courses of the wind, or the currents of the ocean. We thus arrive at the extremely important conviction that all natural bodies which are known to us are equally anmiated, that the distinction which has been made between animate and inanimate bodies does not exist. When a stone is thrown into the air, and falls to earth according to definite laws, or when in a solution of salt a crystal is formed, the phenomenon is neither more nor less a mechanical manifestation of life than the growth and flowering of plants, than the propaga- tion of animals or the activity of their senses, than the perception or the formation of thought in man. This final triumph of the monistic conception of nature consti- tutes the highest and most general merit of the Theory of Descent, as reformed by Darwin.
24 THE HISTORY OF CREATION.
CHAPTER II.
SCIENTIFIC JUSTIFICATION OF THE THEORY OF DE- SCENT. HISTORY OF CREATION ACCORDING TO
LINN^US.
The Theory of Descent, or Doctrine of Filiation, as the Monistic Explana- tion of Organic Natural Phenomena. — Its Comparisoa with Newton's Theory of Gravitation. — Limits of Scientific Explanation and of Human Knowledge in general. — All Knowledge founded originally on Sensuous Experience, d posteriori. — Transition of d posteriori knowledge, by In- heritance, into d priori knowledge. — Contrast between the Supernatural Hypotheses of the Creation according to Linnseus, Cuvier, Agassiz, and the Natural Theories of Development according to Lamarck, Goethe, and Darwin. — Connection of the former with the Monistic (mechanical), of the latter with the Dualistic Conception of the Universe. — Monism and Materialism. — Scientific and Moral Materialism. — The History of Creation according to Moses. — Linnaeus as the Founder of the Systematic Description of Natui'e and Distinction of Species. — Linnaeus' Classifica- tion and Binary Nomenclature. — Meaning of Linnaeus' Idea of Species. — His History of Creation. — Linnasus' view of the Origin of Species.
The value which every scientific theory possesses is measured by the number and importance of the objects which can be explained by it, as well as by the simplicity and universality of the causes which are employed in it as grounds of explanation. On the one hand, the greater the number and the more important the meaning of the phenomena explained by the theory, and the simpler, on the other hand, and the more general the causes which the theory assigns as explanations, the greater is its scientific
NEWTON AND DAKWIN. 25
value, the more safely we are guided by it, and the more strongly are we bound to adopt it.
Let us call to mind, for example, that theory which has ranked up to the present time as the greatest achievement of the human mind — the Theory of Gravitation, which Newton, two hundred years ago, established in his Mathe- matical Principles of Natural Philosophy. Here we find that the object to be explained is as large as one can well imagine. He undertook to reduce the phenomena of the motion of the planets, and the structure of the universe, to mathematical laws. As the most simple cause of these in- tricate phenomena of motion, Newton established the law of weight or attraction, the same law which is the cause of the fall of bodies, of adhesion, cohesion, and many other phenomena.
If we apply the same standard of valuation to Darwin's theory, we must arrive at the conclusion that this theory, also, is one of the greatest achievements of the human mind, and that it may be placed quite on a level with Newton's Theory of Gravitation. Perhaps this opinion will seem a little exaggerated, or at any rate very bold, but I hope in the course of this treatise to convince the reader that this estimate is not too high. In the preceding chapter, some of the most important and most general phenomena in organic nature, which have been explained by Darwin's theory, have been named. Among them are the varia- tions in form which accompany the individual development of organisms, most varied and complicated phenomena, which until now presented the greatest difficulties in the way of mechanical explanation, that is, in the tracing of them to active causes. We have mentioned the rudmnen-
26 THE HISTORY OF CREATION.
tary organs, those exceedingly remarkable structures in animals and plants which have no object and refute every teleological explanation seeking for the final purpose of the organism. A great number of other phenomena might have been mentioned, which are no less important, and are ex- plained in the simplest manner by Darwin's reformed Theory of Descent. For the present I will only mention the phenom^ena presented to us by the geographical distri- hution of animals and plants on the surface of our planet, as well as the geological distribution of the extinct and petrified organisms in the different strata of the earth's crust. These important palseontological and geographical phenomena, which were formerly only known to us as facts, are now traced to their active causes by the Theory of Descent.
The same statement applies fui'ther to all the general laws of Comparative Anatomy, especially to the great law of division of labour or seioaration (polymorphism, or dif- ferentiation), a law which determines the form or structure of human society, as well as the organization of individual animals and plants. It is this law which necessitates an ever increasing variety, as well as a progressive develop- ment of organic forms. This law of the division of labour has, up to the present time, been only recognized as a fact, and it, like the law of progressive development, or the law of progress which we perceive active everywhere in the history of nations (as also in that of animals and plants), is explained by Darwin's Doctrine of Descent. Then, if we turn our attention to the great whole of organic nature, if we compare all the individual groups of phenomena of this immense domain of life, it cannot fail to appear, in the light
NATURE OF DARWIN's THEORY. 27
of the Doctrine of Descent, no longer as the ingeniously desig-ned work of a Creator building up according to a definite purpose, but as the necessary consequence of active causes, which are inherent in the chemical combination of matter itself, and in its physical properties.
In fact, we can most positively assert, and I shall justify this assertion in the course of these pages, that by the Doc- trine of Filiation, or Descent, we are enabled for the first time to reduce all organic phenomena to a single law, and to dis- cover a single active cause for the infinitely intricate mechanism of the whole of this rich world of phenomena. In this respect, Darwin's theory stands quite on a level with Newton's Theory of Gravitation ; indeed, it even rises higher than Newton's theory !
The grounds of explanation are equally simple in the two theories. In explaining this most intricate world of phe- nomena, Darwin does not make use of new or hitherto unknown properties of matter, nor does he, as one might suppose, make use of discoveries of new combinations of matter or of new forces of organization ; but it is simply by extremely ingenious combination, by the syn- thetic comprehension, and by the thoughtful compa- rison of a number of well-knoAvn facts, that Darwin has solved the "holy mystery " of the living world of forms. The consideration of the interchanging relations which exist between two general properties of organisms, viz. Inherit- ance and Adaptation, is what has here been of the first importance. Merely by considering the relations between these two vital actions or physiological functions of organ- isms, also further by considering the reciprocal inter-action which all animals and plants, living in one and the same
28 THE HISTORY OF CREATIOX.
place, necessarily exert on one another — solely by the correct estimate of these simple facts, and by skilfully combining them, Darwin has succeeded in finding the true active causes (causag efficientes) of the immensely intricate world of forms in organic nature.
In any case we are in duty bound to accept this theory till a better one be found, which will undertake to explain the same amount of facts in an equally simple manner. Until now we have been in utter want of such a theory. The fundamental idea that all different animal and vege- table forms must be descended from a few or even from one single, most simple primary form, was indeed not new. This idea was long since distinctly formulated — first by the great Lamarck, at the beginning of our century. But Lamarck in reality only expressed the hypothesis of the Doctrine of Filiation, without establishing it by an explanation of the active causes. And it is just the demonstration of these causes which marks the extraordinary progress which Darwin's theory has made beyond that of Lamarck. In the physiological properties of Inheritance and Adaptation of orofanic matter, Darwin discovered the true cause of the genealogical relationship of organisms. It was not possible for the genius of Lamarck in his day to command that colossal material of biological facts which has been collected by the patient zoological and botanical investigations of the last fifty years, and which has been used by Darwin as an overpowering apparatus of evidence.
Darwin's theory is therefore not what his opponents fre- quently represent it as being — an unwarranted hypothesis taken up at random. It is not for zoologists or botanists to accept or reject this as an explanatory theory, as they
DARWINISM NOT AN HYPOTHESIS. 29
please ; they are rather compelled and obliged to accept it, according to the general principle observed in all natural sciences, that we must accept and retain for the explanation of phenomena any theory which, though it has only a feeble basis, is compatible with the actual facts — until it is replaced by a better one. If we do not adopt it, we re- nounce a scientific explanation of phenomena, and this is, in fact, the position which many biologists still maintain. They look upon the whole domain of animate nature as a perfect mystery, and upon the origin of animals and plants, the phenomena of their development and affinities, as quite inexplicable and miraculous; in fact, they will not allow that there can be a true understanding of them.
Those opponents of Darwin who do not exactly \\dsh to renounce a scientific explanation are in the habit of saying, " Darwin's theory of the common origin of the different species is only one hypothesis; we oppose to it another, the hypothesis that the individual animal and vegetable species have not developed one from another by descent, but that they have come into existence independently of one another, by a still undiscovered law of nature." But as long as it is not shown how this coming into existence is to be conceived of, and what that " law of nature " is — as long as not even probable grounds of explanation can be brought forward to account for the independent coming into existence of animal and vegetable species, so long this counter-hypothesis is in fact no hypothesis, but an empty unmeaning phrase. Darwin's theory ought, moreover, not to be called an hypothesis. For a scientific hypothesis is a supposition, postulating the existence of unknown
properties or motional phenomena of natural bodies, wliich 3
30 THE HISTOEY OF CREATION.
properties have not as yet been observed by the experience of the senses. But Da^^win's theory does not assume such unknown conditions ; it is based upon general properties of organisms that have long been recognized, and — as has been remarked — it is the exceedingly ingenious and com- prehensive combination of a number of phenomena which had hitherto stood isolated, which gives the theory its extraordinarily great and intrinsic value. By it we are for the first time in a position to demonstrate an active cause for all the known morphological phenomena in the animal and vegetable kingdoms; and, in fact, this cause is always one and the same, viz. the alternate action of Adap- tation and Inheritance, therefore a physiological, that is, a physico-chemical or mechanical, relationship. For these reasons the acceptance of the Doctrine of Filiation, as mechanically established by Darwin, is a binding and un- avoidable necessity for the whole domain of zoology and botany.
As, therefore, in my opinion the immense importance of Darwin's theory lies in the fact that it has mechanically explained those organic phenomena of for'.ns which had hitherto been unexplained, it is perhaps necessary that I should here say a few words about the different ideas con- nected with the word " explanation." It is very frequently said, in opposition to Darwin's theory, that it does indeed explain those phenomena by Inheritance and Adaptation, but that it does not at the same time explain those pro- perties of organic matter, and that therefore we do not arrive at first causes. This objection is quite correct, but it applies equally to all explanations of phenomena. We no- where arrive at a knowledge of fii'st causes. The origin of
INNATE KNOWLEDGE. 3 I
every simple salt crystal, which we obtain by evaporating its mother liquor, is no less mysterious to us, as far as con- cerns its first cause, and in itself no less incomprehensible than the origin of every animal which is developed out of a simple cell. In explaining the most simple physical or chemical phenomena, as the falling of a stone, or the forma- tion of a chemical combination, we arrive, by discovering and establishing the active causes — for example, the gravi- tation or the chemical affinity — at other remoter phenomena, which in themselves are mysterious. This arises from the limitation or relativity of our powers of understanding. We must not forget that human knowledge is absolutely limited, and possesses only a relative extension. It is, in its essence, limited by the very nature of our senses and of our brains.
All knowledge springs from sensuous perceptions. In opposition to this statement, the innate, d priori know- ledge of man may be brought up ; but we can see that the so-called d priori knowledge can by Darwin's theory be proved to have been acquired d posteriori, being based on experience as its first cause. Knowledge which is based originally upon purely empirical observations, and which is therefore a purely sensuous experience, but has then been transmitted from generation to generation by inheritance, appears in later generations as if it were independent, innate, and a priori. In our late animal ancestors, all our so-called " a priori knowledge " was originally acquired d posteriori, and only gradually became d p)riori by inherit- ance. It is based in the first instance upon experiences, and by the laws of Inheritance and Adaptation we can positively prove that knowledge d priori and knowledge d
32 THE HISTORY OF CREATION.
posteriori cannot rightly be placed in opposition, as is usually done. On the contrary, sensuous experience is the original source of all knowledge. For this reason alone, all oui' knowledge is limited, and we can never apprehend the first causes of any phenomena. The force of crystal- lization, the force of gravitation, and chemical affinity remain in themselves just as incomprehensible as do Adaptation and Inheritance.
Seeing that Darwin's theory explains from a single point of view the totality of all those phenomena of which we have given a brief survey, that it demonstrates one and the same quality of the organism as the active cause in all cases, we must allow that it gives us for the present all that we can desire. Moreover, we have good reason to hope that at some future time we shall learn to explain the first causes at which Darwin has arrived, namely, the properties of Adaptation and Inheritance ; and that we shall succeed in discovering in the composition of albuminous matter certain molecular relations as the remoter, simpler causes of these phenomena. There is indeed no prospect of this in the immediate future, and we content ourselves for the present with the tracing back of organic phenomena to two mysterious properties, just as in the case of Newton's theory we are satisfied with tracing the planetary motions to the force of gravitation, which itself is likewise a mys- tery to us and not cognizable in itself.
Before commencing our principal task, which is the care- ful discussion of the Doctrine of Descent, and the conse- quences that arise out of it, let us take an historical retro- spect of the most important and most widely spread of those views, which before Darwin men had elaborated concernin^^
I
THE MOSAIC COSMOGENY. 33
organic creation, and the coming into existence of the many animal and vegetable species. In doing this I have no inten- tion of entertaining the reader with a statement of all the innumerable stories about the creation which have been current among the different human species, races, or tribes. However interesting and gratifying this task would be, from an ethnographical point of view, as well as in a history of civilization, it would lead us here much too far from our subject. Besides, the great majority of all these legends about creation bear too clearly the stamp of arbi- trary fiction, and of a want of a close observance of nature, to be of interest in a scientific treatment of the history of crea- tion. I shall therefore only select the Mosaic history from among those that are not founded on scientific investigation, on account of the unparalleled influence which it has gained in the western civilized world ; and then I shall immedi- ately take up the scientific hypothesis about creation, which originated with Linnseus as late as the commencement of last century.
All the different conceptions which man has ever formed about the coming into existence of the diflferent animal and vegetable species may conveniently be divided into two great contrasted groups — the natural and supernatural his- tories of creation.
These two groups, on the whole, correspond with the two different principal forms of the human notions of the uni- verse which we have already contrasted as the ruionistic and the dualistic conception of nature. In the usual dualistic or teleological (vital) conception of the universe, organic nature is regarded as the purposely executed production of a Creator working according to a definite plan. Its adherents see in
34 THE HISTOEY OF CREATION.
every individual species of animal and plant an " embodied creative tliouglit," the material expression of a definite first cause (causa finalis) acting for a set purpose. They must necsssarily assume supernatural (not mechanical) processes for the origin of organisms. With justice, we may therefore designate their scheme of the world's gTowth as the Super- natural History of Creation. Among all such teleological histories of creation, that of Moses has gained the gTcatest influence, since even so -distinguished a naturalist as Lin- na3us has claimed admittance for it in Natural Science. Cuvier's and Agassiz's views of creation also belong to this group, as do in fact those of the great majority of both scientific and unscientific men.
On the other hand, the theory of development carried out by Darwin, which we shall have to treat of here as the Non- Tiiiraculous or Natural History of Creation, and which has already been put forward by Goethe and Lamarck, must, if carried out logically, lead to the monistic or mechan- ical (causal) conception of the universe. In opposition to the dualistic or teleological conception of natm-e, our theory considers organic, as well as inorganic, bodies to be the neces- sary products of natural forces. It does not see in every in- dividual species of animal and plant the embodied thought of a personal Creator, but the expression for the time being of a mechanical process of development of matter, the ex- pression of a necessarily active cause, that is, of a mechanical cause (causa efiiciens). Where teleological Dualism seeks the arbitrary thoughts of a capricious Creator in the miracles of creation, causal Monism finds in the process of develop- ment the necessary efiects of eternal immutable laws of nature.
MATERIALISM. 35
The Monism here maintained by us is often considered identical with Materialism. Now, as Darwinism, and in fact the whole theory of development, has been designated as " materialistic" I cannot avoid here at once guarding myself against this ambiguous word, and against the malice with which, in certain quarters, it is employed to stigmatize our doctrine.
By the word "Materialism',' two completely different things are very frequently confounded and mixed up, which in reality have nothing Avhatever to do with each other, namely, scientific and moral materialism. Scientific mate- rialism, which is identical with our Monism, afiirms in reality no more than that everything in the world goes on naturally — that every effect has its cause, and every cause its effect. It therefore assigns to causal law — that is, the law of a necessary connection between cause and effect — its place over the entire series of phenomena that can be known. At the same time, scientific materialism positively rejects every belief in the miraculous, and every conception, in whatever form it appears, of supernatural processes. Accordingly, nowhere in the whole domain of human know- ledge does it recognize real metaphysics, but throughout only physics ; through it the inseparable connection between matter, form, and force becomes self evident. This scientific materialism has long since been so universally acknowledged in the wide domain of inorganic science, in Physics and Chemistry, in Mineralogy and Geology, that no one now doubts its sole authority. But in Biology, or Organic science, the case is very different; here its value is still continually a matter of dispute in many quarters. There is, however, nothing else which can be set up against it, excepting the
3^ THE HISTORY OF CREATION.
metaphysical spectre of a vital power, or empty theological dogma. If we can prove that all nature, so far as it can be known, is only one, that the same "great, eternal, iron laws" are active in the life of animals and plants, as in the growth of crystals and in the force of steam, we may with reason i^naintain the monistic or mechanical view of things throughout the domain of Biology — in Zoology and Botany — whether it be stigmatized as "materialism " or not. In such a sense all exact science, and the law of cause and effect at its head, is purely materialistic.
Moral, or ethical Materialism, is something quite distinct from scientific materialism, and has nothing whatever in common with the latter. This real materialism proposes no other aim to man in the course of his life than the most refined possible gratification of his senses. It is based on the delusion that purely material enjoyment can alone give satisfaction to man ; but as he can find that satisfaction in no one form of sensuous pleasure, he dashes on weariedly from one to another. The profound truth that the real value of life does not lie in material enjoyment, but in moral action — that true happiness does not depend upon external possessions, but only in a virtuous course of Life — this is unknown to ethical materialism. We therefore look in vain for such materialism among naturalists and phi- losophers, whose highest happiness is the intellectual enjoyment of Nature, and whose highest aim is the know- ledge of her laws. We find it in the palaces of ecclesi- astical princes, and in those hypocrites who, under the outward mask of a pious worship of God, solely aim at hierarchical tyranny over, and material spoliation of, their felloAv-men. Blind to the infinite grandeur of the so-called
MOKAL MATERIALISM. 37
"raw material," and the glorious world of phenomena arising* from it — insensible to the inexhaustible charms of Nature, and without a knowledge of her laws — they stigmatize all natural science, and the culture arising from it, as sinful " materialism," while really it is this which they themselves exhibit in a most shocking form. Satisfactory proofs of this are furnished, not only by the whole history of the Catholic Popes, with their long series of crimes, but also by the history of the morals of orthodoxy in every form of religion.
In order, then, to avoid in future the usual confusion of this utterly objectionable Moral Materialism with our Scientific Materialism, we think it necessary to call the latter either Monism or Realism. The principle of this Monism is the same as what Kant terms the " principle of mechanism," and of which he expressly asserts, thsit without it there can he no natural science at all. This principle is quite inseparable from our Non-miraculous History of Crea- tion, and characterizes it as opposed to the teleological belief in the miracles of a Supernatural History of Creation.
Let us now first of all glance at the most important of all the supernatural histories of creation, I mean that of Moses, as it has been handed down to us in the Bible, the ancient document of the history and laws of the Jewish people. The Mosaic history of creation, since in the first chapter of Genesis it forms the introduction to the Old Testament, has enjoyed, down to the present day, general recognition in the whole Jewish and Christian world of civilization. Its extraordinary success is explained not only by its close connection with Jewish and Christian doctrines, but also by the simple and natural chain of ideas
38 THE HISTORY OF CREATION.
which runs through it, and which contrasts favourably with the confused mythology of creation current among most of the other ancient nations. First the Lord God creates the earth as an inorganic body ; then he separates light from darkness, then water from the dry land. Now the earth has become inhabitable for organisms, and plants are first created, animals later — and among the latter the inhabitants of the water and the air first, afterwards the inhabitants of the dry land. Finally God creates man, the last of all organisms, in his own image, and as the ruler of the earth.
Two gTeat and fundamental ideas, common also to the non-miraculous theory of development, meet us in this Mosaic hypothesis of creation, with surprising clearness and simplicity — the idea of separation or differentiation, and the idea of progressive development or ])erfecting. Although Moses looks upon the results of the great laws of organic development (which we shall later point out as the necessary conclusions of the Doctrine of Descent) as the direct actions of a constructing Creator, yet in his theory there lies hidden the ruling idea of a progressive development and a difieren- tiation of the originally simple matter. We can therefore bestow our just and sincere admiration on the Jewish lawgiver's gTand insight into natui^e, and his simple and natural hypothesis of creation, without discovering in it a so-called " divine revelation," That it cannot be such is clear from the fact that two great fundamental errors are asserted in it, namely, first, the geocentric error that the earth is the fixed central point of the whole universe, round which the sun, moon, and stars move; and secondly, the anthropocentric error, that man is the premeditated aim of the creation of
THE BIBLE AND SCIENCE. 39
the earth, for whose service alone all the rest of nature is said to have been created. The former of these errors was demolished by Copernicus' System of the Universe in the beginning of the 16th century, the latter by Lamarck's Doctrine of Descent in the beginning of the 19th century.
Although the geocentric error of the Mosaic history was demonstrated by Copernicus, and thereby its authority as an absolutely perfect divine revelation was destroyed, yet it has maintained, down to the present day, such influence, that it forms in many wide circles the principle obstacle to the adoption of a natural theory of development. Even in our century, many naturalists, especially geologists, have tried to bring the Mosaic theory into harmony with the recent results of natural science, and have, for example, interpreted Moses' seven days of creation as seven great geological periods. However, all these ingenious attempts at interpretation have so utterly failed, that they require no refutation here. The Bible is no scientific book, but consists of records of the history, the laws, and the religion of the Jewish people, the high merit of which, as a history of civilization, is not impaired by the fact that in all scientific questions it has no commanding importance, and is full of gross errors.
"We may now make a great stride over more than three thousand years, from Moses, who died about the year 1480 before Christ, to Linnaeus, who was born in the year 1707 after Christ. During this whole period no history of creation was brought forward that gained any lasting importance, or the closer examination of which would here be of any interest. Indeed, during the last fifteen hundred years, since Christianity gained its supremacy, the Mosaic history
40 THE HISTORY OF CREATION.
of creation, together with the dogmas connected with it, has become so generally predominant, that the 19th century is the first that has dared positively to rise against it. Even the great Swedish naturalist, Linnaeus, the founder of modern natural history, linked his System of Nature most closely to the Mosaic history of creation.
The extraordinary progress which Charles Linnaeus made in the so-called descriptive natural sciences, consists, as is well known, in his having established a system of nomencla- ture of animals and plants, which he carried out in a manner so perfectly logical and consistent, that down to the present day it has remained in many respects the standard for all succeeding naturalists engaged in the study of the forms of animals and plants. Although Linnaeus' system was artificial, although in classifying animal and vegetable species he only sought and employed single parts as the foundation for his divisions, it has, nevertheless, gained the greatest success ; firstly, in consequence of its being carried out consistently, and secondly, by its nomenclature of natural bodies, which has become extremely important, and at which we must here briefly glance.
Before Linnaeus' time, many vain attempts had been made to throw light upon the endless chaos of difi'erent animal and vegetable forms (then known) by adopting for them suitable names and groupings ; but Linnaeus, by a happy hit, succeeded in accomplishing this important and difllcult task, when he established the so-called " binary nomenclature." The binary nomenclature, or the twofold designation, as Linnaeus first established it, is still universally applied by all zoologists and botanists, and will, no doubt, maintain itself, for a long time to come, with undiminished authority.
LINN^US' NOMENCLATURE. 4I
It consists in this, that every species of animal and plant is designated by two names, which stand to each other in the same relation as do the christian and surnames of a man. The special name which corresponds with the christian name, and expresses the idea of " a species," serves as the common designation of all individual animals or plants, which are equal in all essential matters of form, and are only distinguished by quite subordinate features. The more general name, on the other hand, corresponding with the surname, and which expresses the idea of a genus, serves for the common designation of all the most nearly similar kinds or species.
According to Linnaeus' plan, the more general and compre- hensive generic name is written first ; the special subor- dinate name of the species follows it. Thus, for example, the common cat is called Felis domestica; the wild cat, Felis catus ; the panther, Felis pardus ; the jaguar, Felis onca ; the tiger, Felis tigris ; the lion, Felis leo. All these six kinds of animals of prey are different species of one and the same genus — Felis. Or, to add an example from the vege- table kingdom, according to Linnseus' designation the pine is Pinus abies ; the fir, Pinus picea ; the larch, Pinus larix ; the Italian pine, Pinus pinea ; the Siberian stone pine, Pinus cembra ; the knee timber, Pinus mughus ; the common pine, Pinus silvestris. All these seven kinds of pines are different species of one and the same genus — Pinus.
Perhaps this advance made by Linnaeus may seem to some only of subordinate importance in the practical distinction and designation of the variously formed organisms. But in reality it was of the very greatest importance, both from a practical and theoretical point of view. For now, for the
42 THE HISTORY OF CREATION.
first time, it became possible to arrange the immense mass of different organic forms according to tlieir greater or less degree of resemblance, and to obtain an easy survey of the general outlines of sucb a "system." Linnseus facilitated tbe tabulation and survey of this " system " of plants and animals still more by placing together the most nearly similar genera into so-called orders (ordines) ; and by uniting the most nearly similar orders into still more com- prehensive main divisions or classes. Thus, according to Linnaeus, each of the two organic kingdoms were broken up into a number of classes, the vegetable kingdom into twenty- four, and the animal kingdom into six. Each class again contains several orders. Every single order may contain a number of genera, and, again, every single genus several species.
Valuable as was Linnaeus' binary nomenclature in a prac- tical way, in bringing about a comprehensive systematic distinction, designation, arrangement, and division of the organic world of forms, yet the incalculable theoretical influence which it gained forthwith in relation to the history of creation was no less important. Even now all the important fundamental questions as to the history of creation turn finally upon the decision of the very remote and unimportant question, What really are kinds or species ? Even now the idea of organic species may be termed the central point of the whole question of creation, the disputed centre, about the difierent conceptions of which Darwinists and Anti-Darwinists fight.
According to Darwin's opinion, and that of his adherents, the difierent species of one and the same genus of animals and plants are nothing else than difierently developed
WHAT IS A SPECIES 5 43
descendants of one and the same original primary form. The different kinds of pine mentioned above would accord- ingly have originated from a single primaeval form of pine. In like manner the origin of aU the species of cat mentioned above would be traced to a single common form of Felis, the ancestor of the whole genus. But further, in accordance with the Doctrine of Descent, all the different genera of one and the same order ought also to be descended from one common primary ancestor, and so, in like manner, all ordres of a class from a single primary form.
On the other hand, according to the idea of Darwin's opponents, all species of animals and plants are quite in- dependent of each other, and only the individuals of each species have originated from a single primary form. But if we ask them how they conceive these original primary forms of each species to have come into existence, they answer with a leap into the incomprehensible, " They were created."
Linnaeus himself defined the idea of species in this manner by saying, " There are as many different species as there were different forms created in the beginning by the infinite Being." ( " Species tot sunt diversse, quot diversas formas ab initio creavit infinitum ens.") In this respect, therefore, he follows most closely the Mosaic history of creation, which in the same way maintains that animals and plants were created "each one after its kind." Linnseus, accepting this, held that originally of each species of animals and plants either a single individual or a pair had been created ; in fact a pair, or, as Moses says, "a male and a female " of those species which have separate sexes, but of those species in which each individual combines both sexual organs (hermaphrodites), as for instance the earth-
44 THE HISTORY OF CREATION.
worm, the garden and vineyard snails, as well as the great majority of plants, a single individual.
Linn&eus further follows the Mosaic legend in regard to the flood, by supposing that the great general flood destroyed all existing organisms, except those few individuals of each species (seven pairs of the birds and of clean animals, one pair of unclean animals) which Noah saved in the ark, and which were placed again on land, on Mount Ararat, after the flood had subsided. He tried to explain the geographical difficulty of the living together of the most different animals and plants, as follows : Mount Ararat, in Armenia, being situated in a warm climate, and rising over 16,000 feet in height, combines in itself the conditions for a temporary common abode of such animals as live in different zones. Accordingly, animals accustomed to the polar regions could climb up the cold mountain ridges, those accustomed to a warm climate could go down to the foot of the mountain, and the inhabitants of a temperate zone could remain mid- way up the mountain. From this point it was possible for them to spread north and south over the earth.
It is scarcely necessary to remark that this Linneean hypothesis of creation, which evidently was intended to harmonize most closely with the prevailing belief in the Bible, requires no serious refutation. When we consider Linnseus' clearness and sagacity in other matters, we may doubt whether he believed it himself As to the simulta- neous origin of all individuals of each species from one pair of ancestors respectively (or in the case of the hermaphro- dite species, from one original hermaphrodite), it is clearly quite untenable ; for, apart from other reasons, in the first days after the creation, the few animals of prey would have
LINN^US HISTORY OF CREATION. 45
sufficed to have utterly demolished all the herbivorous animals, as the herbivorous animals must have destroyed the few individuals of the different species of plants. The existence of such an equilibrium in the economy of nature as obtains at present cannot possibly be conceived, if only one individual of each species, or only one pair, had originally and simul- taneously been created.
Moreover, how little importance Linnseus himself attached to this untenable hypothesis of creation is clear, among other things, from the fact that he recognized Hyhridism (crossing) as a source of the production of new species. He assumed that a great number of independent new species had originated by the interbreeding of two different species. Indeed, such hybrids are not at all rare in nature, and it is now proved that a great number of species, for example, of the genus Rubus (bramble), mullen (Verbascum), willow (Salix), thistle (Cirsium), are hybrids of different species of these genera. We also know of hybrids between hares and rabbits (two species of the genus Lepus), further of hybrids between different species of dog (genus Canis), etc., which can be propagated as independent species.
It is certainly very remarkable that Linnseus asserted the physiological (therefore mechanical) origin of new species in this process of hybridism. It clearly stands in direct opposition to the supernatural origin of the other species by creation, which he accepted as put forward in the Mosaic account. The one set of species would therefore have originated by dualistic (teleological) creation, the other by monistic (mechanical) development.
The great and well merited authority which Linnseus gained by his systematic classification and by his other
46 THE HISTORY OF CREATION.
services to Biology, was clearly the reason why his views of creation also remained, throughout the whole of the last century, undisputed and generally recognized. If through- out systematic Zoology and Botany the distinctions, classification, and designations of species, introduced by Linnaeus, and the dogmatic ideas connected therewith had not been maintained — ^more or less unaltered — we should be at a loss to understand how his idea of an independent creation of single species could have stood, by itself, down to the present day. It is only owing to his great authority, and through his attaching himself to the prevail- ing Biblical belief, that his hypothesis of creation has retained its position so long.
CHAPTER III.
THE HISTORY OF CREATION ACCORDING TO CUYIER
AND AGASSIZ.
General Theoretical Meaning of the Idea of Species. — Distinction between the Theoretical and Practical Definition of the Idea of Species. — Cuvier's Definition of Species. — Merits of Cuvier as the Founder of Comparative Anatomy. — Distinction of the Fonr Principal Forms (types or branches) of the Animal Kingdom, by Cuvier and Bar. — Cuvier's Services to Palaeontology. — His Hypothesis of the Revolutions of our Globe, and the Epochs of Creation separated by them. — Unknown Supernatural Causes of the Kevolutions, and the subsequent New Creations. — Agassiz's Teleological System of Nature. — His Conception of the Plan of Creation, and its six Categories (groups in classification). — Agassiz's Views of the Creation of Species. — Eude Conception of the Creator as a man-like being in Agassiz's Hypothesis of Creation. — Its internal Inconsistency and Contradictions with the important Palaeontological Laws discovered by Agassiz.
The real matter of dissension in the contest carried on by naturalists as to the origin of organisms, their creation and development, lies in the conceptions which are enter- tained about the nature of species. Naturalists either agree with Linnaeus, and look upon the different species as distinct forms of creation, independent of one another, or they assume with Darwin their blood-relationship. If we share Linnaeus' view (which was discussed in our last chapter), that the different organic species came into existence independently — that they have no blood-relation-
48 THE HISTORY OF CEEATION.
ship — we are forced to admit that they were created independently, and we must either suppose that every single organic individual was a special act of creation (to which surely no naturalist will agree), or we must derive all individuals of every species from a single in- dividual, or from a single pair, which did not arise in a natural manner, but was called into being by command of a Creator. In so doing, however, we tm^n aside from the safe domain of a rational knowledge of nature, and take refuge in the mythological behef in miracles.
If, on the other hand, with Darwin, we refer the simi- larity of form of the different species to real blood-relation- ship, we must consider all the different species of animals and plants as the altered descendants of one or a few most simple original forms. Viewed in this way, the Natural System of organisms (that is, their tree-like and branching arrangement and division into classes, orders, families, genera, and species) acquires the significance of a real genea- logical tree, whose root is formed by those original archaic forms which have long since disappeared. But a truly natural and consistent view of organisms can assume no supernatural act of creation for even those simplest original forms, but only a coming into existence by 'spontaneous generation* (archigony, or generatio spontanea). From Darwin's view of the nature of species, we arrive there- fore at a natural theory of development; but from Lin- nseus' conception of the idea of species, we must assume a supernatural dogma of creation.
Most naturalists after Linnseus, whose great services in
♦Archebiosis (Bastian), Abiogenesis (Huxley).
THE DOGMA OF SPECIES. 49
systematic and descriptive natural history won for him such high authority, followed in his footsteps, and without further inquiry into the origin of organization, they assumed, in the sense of Linnaeus, an independent creation of individual species, in conformity with the Mosaic account of creation. The foundation of their conception was based upon Lin- naeus' words: "There are as many different species as there were different forms created in the beginning by the Infinite Being." We must here remark at once, without going further into the definition of species, that all zoologists and botanists in their classificatory systems, in the practical dis- tinction and designation of species of animals and plants, never troubled, or even could trouble, themselves in the slightest degree about this assumed creation of the parent forms. In reference to this, one of our first zoologists, the ingenious Fritz Mliller, makes the following striking obser- vation : " Just as in Christian countries there is a catechism of morals, which every one knows by heart, but which no one considers it his duty to follow, or expects to see foUowed by others, — so zoology also has its dogmas, which are just as generally professed as they are denied in practice." (Fiir Darwin, p. 71.) ^^
Linnaeus' venerated dogma of species is just such an irrational dogma, and for that very reason it is powerful. Although most naturalists blindly submitted to it, yet they were, of course, never in a position to demonstrate the descent of individuals belonging to one species from the common, originally created, primitive form. Zoologists and botanists, in their systems of nomenclature, confined themselves entirely to the similarity of forms, in order to distinguish and name the different species. They placed in one species
50 THE HISTORY OF CREATION.
all organic individuals wLicli were very similar, or almost identical in form, and which could only be distinguished from one another by very unimportant differences. On the other hand, they considered as different species those individuals which presented more essential or more striking differences in the foiTQation of their bodies. But of course this opened the flood-gates to the most arbitrary proceedings in the systematic distinctions of species. For as all the individuals of one species are never completely alike in all their parts, but as every species varies more or less, no one could point out which degree of variation constituted a really " good species," or which degree indicated a "mere variety.'*
This dogmatic conception of the idea of species, and the arbitrary proceedings connected with it, necessarily led to the most perplexing contradictions, and to the most untenable suppositions. This is clearly demonstrable in the case of the celebrated Cuvier (born in 1769), who next to Linnseus has exercised the gTeatest influence on the study of zoology. In his conception and definition of the idea of species, he agreed on the whole with Linnseus, and shared also his belief in an independent creation of individual species. Cuvier considered their immutability of such importance that he was led to the fooUsh asser- tion— " The immutability of species is a necessary con- dition of the existence of scientific natural history." As Linnreus' definition of species did not satisfy him, he made an attempt to give a more exact and, for syste- matic practice, a more useful definition, in the following words : ''' All those individual animals and plants belong to one species which can be proved to be either descended
cuvier's definition of species. 51
from one another, or from common ancestors, or which are as similar to these as the latter are among themselves."
In dealing with this matter, Cuvier reasoned in the following manner: — "In those organic individuals, of which we know that they are descended from one and the same common form of ancestors — in which, therefore, their com- mon ancestry is empirically proved — there can be no doubt that they belong to one species, whether they differ much or little from one another, or whether they are almost alike or very unlike. Moreover, all those individuals also belong to this species which differ no more from the latter (those proved to be derived from a common stock) than these differ from one another." In a closer examination of this definition of species given by Cuvier, it becomes at once evident that it is neither theoretically satisfactory nor practically appli- cable. Cuvier, with this definition, began to move in the same circle in which almost all subsequent definitions of species have moved, through the assumption of -their immutability.
Considering the extraordinary authority which George Cuvier has gained in the science of organic nature, and in con- sequence of the almost unlimited supremacy which his views exercised in zoology, during the first half of our century, it seems appropriate here to examine his influence a little more closely. This is all the more necessary as we have to com- bat, in Cuvier, the most formidable opponent to the Theory of Descent and the monistic conception of nature.
One of the many and great merits of Cuvier is that he stands forth as the founder of Comparative Anatomy. While Linnaeus established the distinction of species, genera, orders, and classes mostly upon external characters, and upon sepa-
52 THE HISTOEY OF CEEATION.
rate and easily discoverable signs in the number, size, place, and form of individual organic parts of the body, Cuvier penetrated much more deeply into the essence of organiza- tion. He demonstrated great and wide differences in the inner structure of animals, as the real foundation of a scientific knowledge and classification of them. He dis- tinguished natural families in the classes of animals, and established his natural system of the animal kingdom on their comparative anatomy.
The progress from Linnseus' artificial system to Cuvier's natural system was exceedingly important. Linnaeus had arranged all animals in a single series, which he divided into six classes, two classes of Invertebrate, and four classes of Vertebrate animals. He distinguished these artificially, according to the nature of their blood and heart. Cuvier, on the other hand, showed that in the animal kingdom there were four great natural divisions to be distinguished, which he termed Principal Forms, or General Plans, or Branches of the animal kingdom (Embranchments), namely — 1. The Vertebrate animals ( Vertebra ta) ; 2. The Articulate animals (Articulata) ; 3. The Molluscous animals (Mollusca) ; and 4. The Radiate animals (Radiata). He further demonstrated that in each of these four branches a peculiar plan of struc- ture or type was discernible, distinguishing each branch from the three others. In the Vertebrate animals it is dis- tinctly expressed by the form of the skeleton, or bony framework, as also by the structure and position of the dorsal nerve-chord, apart from many other peculiarities. The Articulate animals are characterized by their ventral nerve-chord and their dorsal heart. In Molluscs the sack- shaped and non-articulate body is the distinguishing feature.
CUVIER AND BAER. 53
The Radiate animals, finally, differ from tlie three other principal forms by their body being the combination of fonr or more main sections united in the form of radii (antimera).
The distinction of these four principal forms of animals, which has become extremely productive in the development of zoology, is commonly ascribed entirely to Cuvier. How- ever, the same thought was expressed almost simultaneously, and independently of Cuvier, by Bar, one of the greatest naturalists, and still living, who did the most eminent service in the study of animal development. Bar showed that in the development of animals, also, four different main forms (or types) must be distinguished. ^^ These correspond with the four plans of structure in animals, which Cuvier distin- guished on the ground of comparative anatomy. Thus, for example, the individual development of all Vertebrate ani- mals agrees, from the commencement, so much in its funda- mental features that the germs or embryos of different Vertebrate animals (for example, of reptiles, birds, and mammals) in their earlier stages cannot be distinguished at all. It is only at a late stage of development that there gradually appear the more marked differences of form which separate those different classes and orders from one another. The plan of structure, which shows itself in the individual development of Articulate animals (insects, spiders, crabs), is from the beginning essentially the same in all Articulate animals, but different from that of all Vertebrate animals. The same holds good, with certain limitations, in Molluscous and Radiated animals.
Neither Bar, who arrived at the distinction of the four animal types or principal forms through the history of the individual development (Embryology), nor Cuvier, who 4
54 THE HISTORY OF CREATION.
arrived at the same conclusion by means of comparative anatomy, recognized the true cause of this difierence. This is disclosed to us by the Theory of Descent. The wonderful and astonishing similarity in the inner organ- ization and in the anatomical relations of structure, and the still more remarkable agreement in the embryonic de- velopment of all animals belonging to one and the same type (for example, to the branch of the Vertebrate animals), is explained in the simplest manner by the supposition of their common descent from a single primary original form. If this view is not accepted, then the complete agreement of the most different Vertebrate animals, in their inner struc- ture and their manner of development, remains perfectly inexplicable. In fact it can only be explained by the law of inheritance.
Next to the comparative anatomy of animals and the systematic zoology founded anew by it, it was specially to the science of petrifactions, or Palaeontology, that Cuvier rendered great service. We must draw special attention to this, because these very palseontological views, and the geological ideas connected with them, were held almost universally in the highest esteem during the first half of the present century, and caused the greatest hindrance to the working out of a truly natural history of creation.
Petrifactions, the scientific study of which Cuvier pro- moted at the beginning of our century in a most ex- tensive manner, and established quite anew for the Verte- brate animals, play one of the most important parts in the " non-miraculous history of creation." For these remains and impressions of extinct animals and plants, preserved to us in a petrified condition, are the true " monuments of the
FOSSIL ORGANISMS. 55
creation/' the infallible and indisputable records wliicb fix the correct history of organisms upon an irrefragable founda- tion. All petrified or fossil remains and impressions tell us of the forms and structure of such animals and plants as are either the progenitors and ancestors of the present living organisms, or they are the representatives of extinct colla- teral lines, which, together with the present living organisms, branched ofi" from a common stem.
These inestimable records of the history of creation throughout a long period played a subordinate part in science. Their true nature was indeed correctly understood, even more than five hundred years before Christ, by the great Greek philosopher, Xenophanes of Colophon, the same who founded the so-called Eleatic philosophy, and who was the first to demonstrate with convincing precision that all conceptions of personal gods result in more or less rude anthropomorphism.
Xenophanes for the first time asserted that the fossil im- pressions of animals and plants were real remains of formerly living creatures, and that the mountains in whose rocks they were found must at an earlier date have stood under water. But although other great philosophers of antiquity, and among them Aristotle, also possessed this true know- ledge, yet throughout the illiterate Middle Ages, and even with some naturalists of the last century, the idea prevailed that petrifactions were so-called freaks of nature (lusus naturae), or products of an unknown formative power or instinct of nature (nisus formativus, vis plastica). Respect- ing the nature of this mysterious and mystic creative power, the strangest ideas were formed. Some believed that this constructive power — the same to which they also
56 THE HISTORY OF CKEATION.
ascribed the coming into existence of the present species of animals and plants — had made numerous attempts to create organisms of different forms, but that these attempts had only partially succeeded, had often failed, and that petrifac- tions were nothing more than such unsuccessful attempts. According to others, petrifactions originated from the in- fluence of the stars upon the interior of the earth.
Others, again, had the still cruder notion that the Creator had first made models (out of mineral substances — for example, of gypsum or clay) of those forms of animals and plants which he afterwards executed in organic substances, and into which he breathed his living breath ; petrifactions were accordingly such rude inorganic models. Even as late as the last century these crude ideas prevailed, and it was assumed, for example, that there existed a special " seminal air," which was said to penetrate into the earth with the water, and by fructifying the stones formed petrifactions or " stony flesh " (caro fossilis).
It took a very long time before the simple and natural view was accepted, namely, that petrifactions are in reality nothing but what they appear to simple observation — the indestructible remains of extinct organisms. It is true the celebrated painter, Leonardo da Vinci, in the 15th century, ventured to assert that the mud which was constantly deposited by water was the cause of petrifactions, as it surrounded the indestructible shells of mussels and snails which lay at the bottom of the waters, and gradually turned them into solid stone. The same idea was maintained in the IGth century by a Parisian potter, Palissy by name, who became celebrated on account of his invention of china. However, the so-called " professional men " were
cuvier's work in paleontology. 57
very far from paying any regard to these correct assertions of a simple and healthy human understanding; it was not till the end of the last century that it was generally accepted, in consequence of the foundation of the Neptunian geology by Werner.
The foundation of a more strictly scientific palaeontology, however, belongs to the beginning of our century, when Cuvier published his classic researches on petrified Verte- brate animals, and when his great opponent, Lamarck, made known his remarkable investigations on fossil Invertebrate animals, especially on petrified snails and clams. In Cuvier's celebrated work "On the Fossil Bones" of Vertebrate animals — principally of mammals and reptiles — we see that he had already arrived at the knowledge of some very important and general paleeontological laws, which are of great con- sequence to the history of creation. Foremost among them stands the assertion that the extinct species of animals, whose remains we find petrified in the difierent strata of the earth's crust, lying one above another, difier all the more strikingly from the still living kindred species of animals the deeper those strata lie — in other words, the earlier the animals lived in past ages. In fact, in every per- pendicular section of the stratified crust of the earth we find that the difierent strata, deposited by the water in a certain historical succession, are characterized by different petrifactions, and that these extinct organisms become more like those of the present day the higher the strata lie ; in other words, the more recent the period in the earth's history in which they lived, died, and became encrusted by the deposited and hardened strata of mud.
However important this general observation of Cuvier's
58 THE HISTORY OF CREATION.
was in one sense, yet in another it became to him the source of a very serious error. For as he considered the charac- teristic petrifactions of each individual group of strata (which had been deposited during one main period of the earth's history) to be entirely different from those of the strata lying above or below, and as he erroneously believed that one and the same species of animal was never found in two succeeding groups of strata, he arrived at the false idea, which was accepted as a law by most subsequent naturalists, that a series of quite distinct periods of creation had succeeded one another. Each period was supposed to have had its special animal and vegetable world, each its peculiar specific Fauna and Flora.
Cuvier imagined that the whole history of the earth's crust, since the time when living creatures had fiirst appeared on the surface, must be divided into a number of perfectly distinct periods, or divisions of time, and that the individual periods must have been separated li'om one another by peculiar revolutions of an unknown nature (cataclysms, or catastrophes). Each revolution was followed by the utter annihilation of the till then existing animals and plants, and after its termination a completely new creation of organic forms took place. A new world of animals and plants, absolutely and specifically distinct from those of the preced- ing historical periods, was called into existence at once, and now again peopled the globe for thousands of years, till it again perished suddenly in the crash of a new revolution.
About the nature and causes of these revolutions, Cuvier expressly said that no idea could be formed, and that the present active forces in nature were not sufficient for their explanation. Cuvier points out four active causes as the
cuvier's cataclysms. 59
natural forces, or mechanical agents, at present constantly but slowly at work in changing the earth's surface : first, rain, which washes down the steep mountain slopes and heaps up debris at their foot; secondly, flowing waters, which carry away this debris and deposit ii as mud in stagnant waters ; thirdly, the sea, whose bieakers gnaw at the steep sea coasts, and throw up " dunes " on the flat sea margins ; finally and fourthly, vdcanos, which break through and heave up the strata of the earth's hardened crust, and pile up and scatter about the products of their eruptions. Whilst Cuvier recognizes the constant slow transformation of the present surface of the earth by these four mighty causes, he asserts at the same time that they would not have sufficed to effect the revolutions of the remote ages, and that the anatomical structure of the earth's surface cannot be explained by the necessary action of those mechanical agents : the great and marvellous revolutions of the whole earth's surface must, according to him, have been rather the effects of very peculiar causes, completely unknown to us ; the usual thread of development was broken by them, and the course of nature altered.
These views Cuvier explained in a special work " On the Revolutions of the Earth's Surface, and the Changes which they have wrought in the Animal World." They were maintained, and generally accepted for a long time, and be- came the greatest obstacle to the development of a natural history of the creation. For if such all-destructive revolu- tions had actually occurred, of course a continuity of the development of species, a connecting thread in the organic history of the earth, could not be admitted at all, and we
6o THE HISTORY OF CREATION.
should be obliged to bave recourse to the action of super- natural forces ; tbat is, to tlie interference of miracles in the natural course of things. It is only through miracles that these revolutions of the earth could have been brought about, and it is only through miracles that, after their cessation and at the commencement of each new period, a new animal and vegetable kingdom could have been created. But science has no room for miracles, for by miracles we under- stand an interference of supernatural forces in the naturxl course of development of matter. '
Just as the great authority which Linnseus gained by his system of distinguishing and naming organic species led his successors to a complete ossification, as it were, of the dogmatic idea of species and to a real abuse of the syste- matic distinction implied by it, so the great services which Cuvier had rendered to the knowledge and distinction of extinct species became the ca^use of a general adoption of his theory of revolutions and catastrophes, and of the false views of creation connected therewith. The conse- quence of this was that, during the first half of our century, most zoologists and botanists clung to the opinion that a series of independent periods in the organic history of the earth had existed ; that each period was distinguished by distinct and peculiar kinds of animal and vegetable species ; that these were annihilated at the termination of the period by a general revolution ; and that, after the cessation of the latter, a new world of different species of animals and plants was created.
It is true some independent thinkers, above all the great physical philosopher, Lamarck, even at an early period, set forth a series of weighty reasons which refuted Cuvier's
AGASSIZ ON CEEATION. 6 1
theory of cataclysms, and pointed to a perfectly continuous and uninterrupted developmental history of all the organic inhabitants of the earth through all ages. They maintained that the animal and vegetable species of each period were derived from those of the preceding period, and were only the altered descendants of the former. This true conception, however, being opposed to Cuvier's great authority, was then unable to make way. Nay, even after Cuvier's theory of catastrophies had been completely cast out from the domain of geology by Lyell's classic Principles of Geology, which appeared in 1830, still his idea of the specific dis- tinctness of a series of organic creations maintained its influence, in many ways, in the science of Palaeontology. (Gen. Morph. ii. 312.)
By a curious coincidence, thirteen years ago, almost at the same time that Cuvier's History of Creation received its death-blow by Darwin's book, another celebrated naturalist made an attempt to re-establish it, and to adopt it in the roughest manner, as a part of a teleologico-theological system of nature. This was the Swiss geologist, Louis Agassiz, who attained a great reputation by his theory of glaciers and the ice-period, borrowed from Schimper and Charpentier, and who has been living in North America for many years. He commenced in 1858 to publish a work planned on a very large scale, which bears the title of " Contributions to the Natural History of the United States of North America." The first volume of this work, although large and costly, owing to the patriotism of the Americans, had an unprecedented sale ; its title is, " An Essay on Classi- fication." ^
In this essay Agassiz not only discusses the natural series
62 THE HISTOEY OF CREATION.
of organisms, and the different attempts of naturalists at classification, but also all the general biological phenomena which have reference to it. The history of the development of organisms, both the embryonal and the palseontological, comparative anatomy, the general economy of nature, the geographical and topographical distribution of animals and plants — in short, almost all the general phenomena of organic nature are discussed in Agassiz's Essay on Classifi- cation, and are explained in a sense and from a point of view which is thoroughly opposed to that of Darwin. While Darwin's chief merit lies in the fact that he demon- strates natural causes for the coming into existence of animal and vegetable species, and thereby establishes the mechanical or monistic view of the universe as regards this
o
most difficult branch of the history of creation, Agassiz, on the contrary, strives to exclude every mechanical hypothesis from the subject, and to put the supernatural interference of a personal Creator in the place of the natural forces of matter ; consequently, to establish a thoroughly teleo- logical or dualistic view of the universe. It will not be out of place if I examine a little more closely Agassiz's biological views, and especially his ideas of creation, because no other work of onr opponents treats the important fundamental questions with equal minuteness, and because the utter untenableness of the dualistic conception of nature becomes very evident from the failure of this attempt.
The organic species, the various conceptions of which we have above designated as the real centre of dispute in the opposed views of creation, is looked upon by Agassiz, as by Cuvier and Linnseus, as a form unchangeable in all its essential characteristics. The species may indeed change
A.GASSIZ ON CREATION. 63
and vary witliin certain narrow limits ; never in essential qualities, but only in unessential points. No new species could ever proceed from the changes or varieties of a species. Not one of all organic species, therefore, is ever derived from another, but each individual species has been separately created by God. Each individual species, as Agassiz expresses it, is " an embodied creative thought " of God.
In direct opposition to the fact established by palseonto- logical experience, that the duration of the individual organic species is most unequal, and that many species continue unchanged through several successive periods of the earth's history, while others only existed during a small portion of such a period, Agassiz maintains that one and the same species never occurs in two different periods, but that each individual period is characterized by species of animals and plants which are quite peculiar, and belong to it exclusively. He further shares Cuvier's opinion that the whole of these inhabitants were annihilated by the great and universal revolutions of the earth's surface, which divide two successive periods, and that after its destruction a new and specifically different assemblage of organisms was created. This new creation Agassiz supposes to have taken place in this manner : viz., that at each creation all the inhabitants of the earth, in their full average number of individuals, and in the peculiar relations corresponding to the economy of nature, were, as a whole, suddenly placed upon the earth by the Creator. In saying this he puts himself in opposition to one of the most firmly established and most important laws of animal and vegetable geography — namely, to the law that each species has a single original locality of origin, or a so-called " centre of creation," from
64 THE HISTORY OF CEEATION.
wliicli it has gradually spread over the rest of the earth. Instead of this, Agassiz assumes each species to have been created at several points of the earth's surface, and that in each case a large number of individuals was created.
The " natural system " of organisms, the different groups and categories of which arranged above one another — namely, the branches, classes, orders, families, genera, and species — we consider, in accordance with the Theory of Descent, as different branches and twigs of the organic family- tree, is, according to Agassiz, the direct expression of the divine plan of creation, and the naturalist, while investigat- ing the natural system, repeats the creative thoughts of God. In this Agassiz finds the strongest proof that man is the image and child of God. The different stages of groups or categories of the natural system correspond with the different stages of development which the divine plan of creation had attained. The Creator, in projecting and carrying out this plan, starting from the most general ideas of creation, plunged more and more into specialities. For instance, when creating the animal kingdom, God had in the first place four totally distinct ideas of animal bodies, which he embodied in the difierent structures of the four great, principal forms, types, or branches of the animal kingdom; namely, vertebrate animals, articulate animals, molluscous animals, and radiate animals. The Creator then, having reflected in what manner he might vary these four different plans of structure, next created within each of the four principal forms, several different classes — for example, in the vertebrate animal form, the classes of mammals, birds, reptiles, amphibious animals, and fishes. Then God further reflected u[)on the individual classes, and by
THE CREATOR AS AN ARCHITECT. 65
various modifications in the structure of each class, he pro- duced the individual orders. By further variation in the order, he created natural families. As the Creator further varied the peculiarities of structure of individual parts in each family, genera arose. In further meditation on his plan of creation, he entered so much into detail that in- dividual species came into existence, which, consequently, are embodied creative thoughts of the most special kind. It is only to be regretted that the Creator expressed these most special and most deeply considered "creative thoughts" in so very indistinct and loose a manner, and that he im- printed so vague a stamp upon them, and permitted them to vary so freely that not one naturalist is able to distinguish the "good" from the "bad species," or a genuine species from varieties, races, etc. (Gen. Morph. ii. 373.)
We see, then, according to Agassiz's conception, that the Creator, in producing organic forms, goes to work exactly as a human architect, who has taken upon himself the task of devising and producing as many different buildings as possible, for the most manifold purposes, in the most dif- ferent styles, in various degrees of simplicity, splendour, greatness, and perfection. This architect would perhaps at first choose four difierent styles for all these buildings, say the Gothic, Byzantine, Chinese, and Rococo styles. In each of these styles he would build a number of churches, palaces, garrisons, prisons, and dwelling-houses. Each of these dif- ferent buildings he would execute in ruder and more perfect, in greater and smaller, in simpler and grander fashion, etc. However, the human architect would perhaps, in this respect, be better off than the divine Creator, as he would have perfect liberty in the number of graduated subordinate
66 THE HISTORY OF CREATION.
groups. The Creator, however, according to Agassiz, can only move within six groups or categories : the species, genus, family, order, class, and type. More than these six categories do not exist for him.
When we read Agassiz's book on classification, and see how he carries out and establishes these strange ideas, we can scarcely understand how, with all the appearance of scien- tific earnestness, he can persevere in his idea of the divine Creator as a man-like being (anthropomorphism), for by his explanation of details he produces a picture of the most absurd nonsense. In the whole series of these suppositions the Creator is nothing but an all-mighty man, who, plagued with ennui, amuses himself with planning and constructing most varied toys in the shape of organic species. After having diverted himself with these for thousands of years, they become tiresome to him, he destroys them by a general revolution of the earth's surface, and thus throws the whole of the useless toys in heaps together; then, in order to while away his time with something new and better, he calls a new and more perfect animal and vegetable world into existence. But in order not to have the trouble of beginning the work of creation over again, he keeps, in the main, to his original plan of creation, and creates merely new species, or at most only new genera, and much more rarely new families, new orders, or classes. He never suc- ceeds in producing a new style or type, and always keeps strictly within the six categories or graduated groups.
When, according to Agassiz, the Creator has thus amused himself for thousands of millions of years with constructing and destroying a series of difierent creations, at last (but very late) he is struck with the happy thought of creating
INCONSISTENCY OF AGASSIZ. 67
something like himself, and so makes man in his own image. The end of all the history of creation is thus arrived at and the series of revolutions of the earth is closed. Man, the child and image of God, gives him so much to do, causes him so much pleasure and trouble, that he is wearied no longer, and therefore need not undertake a new creation. It is clear that if, according to Agassiz, we once assign to the Creator entirely human attributes and qualities, and regard his work of creation as entirely analogous to human creative activity, we are necessarily obliged to admit such utterly absurd inferences as those just stated.
The many intrinsic contradictions and perversities in Agassiz's view of creation — a view which necessarily led him to the most decided opposition to the Theory of Descent — ^must excite our astonishment all the more be- cause, in his earlier scientific works, he had in many respects actually paved the way for Darwin, especially by his researches in Palaeontology. Among the numerous investigations which created general interest in the then young science of Palaeontology, those of Agassiz, especially his celebrated work on " Fossil Fish," rank next in import- ance to Cuvier's work, which formed the foundation of the science. The petrified fish, with which Agassiz has made us acquainted, have not only an extremely great import- ance for the understanding of all groups of Vertebrate animals, and their historical development, but we have arrived through them at a sure knowledge of important general laws of development, some of which were first discovered by Agassiz. He it was who drew special atten- tion to the remarkable parallelism between the embryonal and the palseontological development — between ontogeny
68 THE HISTORY OF CREATION.
and phylogeny, which I have abeady (p. 10) claimed as one of the strongest pillars of the Theory of Descent. No one before had so distinctly stated as Agassiz did, that, of the Vertebrate animals, fishes alone existed, at first, that amphibious animals came later, and that birds and mam- mals appeared only at a much later period, further, that among mammals, as among fishes, imperfect and lower orders had appeared first, but more perfect and higher orders at a later period. Agassiz, therefore, showed that the palseontological development of the whole Vertebrate group was not only parallel with the embryonic, but also with the systematic development, that is, with the gi^aduated series which we see everywhere in the system, ascending from the lower to the higher classes, orders, etc.
In the earth's history lower forms appeared first, the higher forms later. This important fact, as well as the agTeement of the embryonic and palaeontological develop- ment, is explained quite simply and naturally by the Doctrine of Descent, and without it is perfectly inex- plicable. This cause holds good also in the great law of 'progressive development, that is, of the historical progress of organization, which is traceable, broadly and as a whole, in the historical succession of all organisms, as well as in the special perfecting of individual parts of animal bodies. Thus, for example, the skeleton of Vertebrate animals acquired at first slowly, and by degrees, that high degree of perfection which it now possesses in man and the other higher Vertebrate animals. This progress, acknowledged in point of fact by Agassiz, necessarily follows from Dar- win's Doctrine of Descent, which demonstrates its active causes. If this doctrine is correct, the perfecting and diver-
DEVELOPMENT OF THE CREATOE. 69
sification of animal and vegetable species must of necessity have gradually increased in the course of the organic history of the earth, and could only attain its highest perfection in most recent times.
The above-mentioned laws of development, together with some other general ones, which have been expressly admitted and justly emphasized by Agassiz, and some of which have first been set forth by him, are, as we shall see later, only explicable by the Theory of Descent, and without it remain perfectly incomprehensible. The conjoint action of In- heritance and Adaptation, as explained by Darwin, can alone be their true cause. But they all stand in sharp and irreconcilable opposition to the hypothesis of creation main- tained by Agassiz, as well as to the idea of a personal Creator who acts for a definite purpose. If we seriously wish to explain those remarkable phenomena and their inter-connection by Agassiz's theory, then we are necessarily driven to the curious supposition that the Creator himself has developed, together with the organic nature which he created and modelled. We can, in that case, no longer rid ourselves of the idea that the Creator himself, like a human being, designed, improved, and finally, with many altera- tions, carried out his plans. " Man grows as higher grow his aims," and the same supposition, so unworthy of a God, must be applied to him. Although, from the reverence with which, in every page, Agassiz speaks o± the Creator, it might appear that, on his theory, we attain to the sublimest conception of the divine activity in nature, yet the contrary is in truth the case. The divine Creator is degi'aded to the level of an idealized man, of an organism progressing in development ! '
70 THE HISTORY OF CREATION.
Considering the wide popularity and great authority which Agassiz's work has gained, and which is perhaps justified on account of earlier scientific services rendered by the author, I have thought it my duty here to show the utter untenableness of his general conceptions. So far as this work pretends to be a scientific history of creation, it is undoubtedly a complete failure. But still it has great value, being the only detailed attempt, adorned with scien- tific arguments, which an eminent naturalist of our day has made to found a teleological or dualistic history of creation. The utter impossibility of such a history has thus been made obvious to every one. No opponent of Agassiz could have refuted the dualistic conception of organic nature and its origin more strikingly than he him- self has done by the intrinsic contradictions which present themselves everywhere in his theory.
The opponents of the monistic or mechanical conception of the world have welcomed Agassiz's work with delight, and find in it a perfect proof of the direct creative action of a personal God. But they overlook the fact that this per- sonal Creator is only an idealized organism, endowed with human attributes. This low dualistic conception of God corresponds with a low animal stage of development of the human organism. The more developed man of the pre- sent day is capable of, and justified in, conceiving that infinitely nobler and sublimer idea of God which alone is compatible with the monistic conception of the universe, and which recognizes God's spirit and power in all phenomena without exception. This monistic idea of God, which belongs to the future, has already been expressed by Giordano Bruno in the following words: — "A spirit exists in all
UNITY OF GOD AND NATUEE. 71
things, and no body is so small but contains a part of the divine substance within itself, by which it is animated." It is of this noble idea of God that Goethe says : — " Certainly there does not exist a more beautiful worship of God than that which needs no image, but which arises in our heart from converse with Nature." By it we arrive at the sublime idea of the Unity of God and NaturOi
72 THE HISTORY OF CREATION.
CHAPTER IV.
THEORY OF DEVELOPMENT ACCORDING TO GOETHE
AND 0IO]N.
Scientific Insufficiency of all Conceptions of a Creation of Individnal Species — Necessity of the Counter Theories of Development. — Historical Survey of the Most Important Theories of Development. — Aristotle. — His Doctrine of Spontaneous Generation. — The Meaning of Natural Philosophy. — Goethe. — His Merits as a Naturalist. — His Metamorphosis of Plants. — His Yertebral Theory of the Skull. — His Discovery of the Mid Jawbone in Man. — Goethe's Interest in the Dispute between Cuvier and Geoffrey St. Hilaire. — Goethe's Discovery of the Two Organic Formative Principles, of the Conservative Principle of Specification (by Inheritance), and of the Progressive Principle of Transformation (by Adaptation). — Goethe's Yiews of the Common Descent of aU Yertebrate Animals, including Man. — Theory of Development according to Gottfried Reinhold Treviranus. — His Monistic Conception of Nature. — Oken. — His Natural Philosophy, — Oken's Theory of Protoplasm. — Oken's Theory of Infusoria (Cell Theory). — Oken's Theory of Development.
All tlie different ideas which we may form of a separate and independent origin of the individual organic species by creation lead us, when logically carried out, to a so- called anthropomorphism, that is, to imagining the Creator as a man-like being, as was shown in our last chapter. The Creator becomes an organism who designs a plan, reflects upon and varies this plan, and finally forms creatiu-es according to this plan, as a human architect would his building. If even such eminent natm^alists as
FAILURE OF TELEOLOGY. 73
Linnaeus, Cuvier, and Agassi z, the principal representatives of the dualistic hypothesis of creation, could not arrive at a more satisfactory view, we may take it as evidence of the insufficiency of all those conceptions which would derive the various forms of organic nature from a creation of individual species.
Some naturalists, indeed, seeing the complete insuffi- ciency of these views, have tried to replace the idea of a personal Creator by that of an unconsciously active and creative Force of Nature ; yet this expression is evidently merely an evasive phrase, as long as it is not clearly shown what this force of nature is, and how it works. Hence these attempts, also, have been absolute failures. In fact, whenever an independent origin of the different forms of animals and plants has been assumed, naturalists have fomid themselves compelled to fall back upon so many "acts of creation," that is, on supernatural interferences of the Creator in the natural course of things, which in all other cases goes on without interference.
It is true that several teleological naturalists, feeling the scientific insufficiency of a supernatural " creation !' have endeavoured to save the hypothesis by wishing it to be understood that creation "is nothing else than a way of coming into being, unknown and inconceivable to us." The eminent Fritz Miiller has cut off from this sophistic evasion every chance of escape by the following striking remark : — " It is intended here only to express in a disguised manner the shamefaced confession, that they neither have, nor care to have, any ojpinion about the origin of species. Accord- ing to this explanation of the word, we might as well speak of the creation of cholera, or syphilis, of the creation of a
74 THE HISTORY OF CREATION.
conflagration, or of a railway accident, as of the creation of man." (Jenaische Zestscrift, bd. v. p. 272.)
In the face, then, of these hypotheses of creation, which are scientifically insufficient, we are forced to seek refuge in the counter-theory of development of organisms, if we wish to come to a rational conception of the origin of organ- isms. We are forced and obliged to do so, even if the theory of development only throws a glimmer of probability upon a mechanical, natural origin of the animal and vege- table species; but all the more if, as we shall see, this theory explains all facts simply and clearly, as well as com- pletely and comprehensively. The theories of develop- ment are by no means, as they often falsely are represented to be, arbitrary fancies, or wilful products of the imagination, which only attempt approximately to explain the origin of . this or that individual organism; but they are theories founded strictly on science, which explain in the simplest manner, from a fijced and clear point of view, the whole of organic natural phenomena, and more especially the origin of organic species, and demonstrate them to be the necessary consequences of mechanical processes in nature.
As I have already shown in the second chapter, all these theories of development coincide naturally with that general theory of the universe which is usually designated as the uniform or monistic, often also as the mechanical or causal, because it only assumes mechanical causes, or causes working by necessity (causae efficientes), for the explanation of natural phenomena. In like manner, on the other hand, the supernatural hypotheses of creation which we have al- ready discussed coincide completely with the opposite view of the universe, which in contrast to the former is called the
THE THEORY OF DESCENT. 75
twofold or dualistic, often the teleological or vital, because it traces the organic natural phenomena to final causes, acting and tuorJcing for a definite purpose (causse finales). It is this deep and intrinsic connection of the difierent theories of creation with the most important questions of philosophy that incites us to their closer examination.
The fundamental idea, which must necessarily lie at the bottom of all natural theories of development, is that of a gradual development of all (even the most perfect) or- ganisms out of a single, or out of a very few, quite simple, and quite imperfect original beings, which came into exist- ence, not by supernatural creation, but by spontaneous generation, or archigony, out of inorganic matter. In reality, there are two distinct conceptions united in this fundamental idea, but which have, nevertheless, a deep in- trinsic connection — namely, first, the idea of spontaneous generation (or archigony) of the original primary beings ; and secondly, the idea of the progressive development of the various species of organisms from those most simple primary beings. These two important mechanical concep- tions are the inseparable fundamental ideas of every theory of development, if scientifically carried out. As it maintains the derivation of the different species of animals and plants from the simplest, common primary species, we may term it also the Doctrine of Filiation, or Theory of Descent; as there is also a change of species connected with it, it may also be termed the Transmutation Theory.
While the supernatural histories of creation must have originated thousands of years ago, in that very remote primitive age when man, first developing out of the monkey- state, began for the first time to think more closely about
76 THE HISTORY OF ^CREATION.
himself, and about the origin of the world around him, the natural theories of development, on the other hand, are necessarily of much more recent origin. These views are met with only among nations of a more matured civilization, to whom, by philosophic culture, the necessity of a know- ledge of natural causes has become apparent; and even among these, only individual and specially gifted natures can be expected to have recognized the origin of the world of phenomena, as well as its course of development, as the necessary consequences of mechanical, naturally active causes. In no nation have these preliminary conditions, for the origin of a natural theory of development, ever existed in so high a degree as among the Greeks of classic antiquity. But, on the other hand, they lacked a close acquaintance with the facts of the processes and forms of nature, and, consequently, the foundation based upon experience, for a satisfactory unravelling of the problem of development. Exact investigation of nature, and the knowledge of nature founded on an experimental basis, was of course almost unknown to antiquity, as well as to the Middle Ages, and is only an acquisition of modern times. We have therefore here no special occasion to examine the natural theories of development of the various Greek philosophers, since they were wanting in the knowledge gained by experience, both of organic and inorganic nature, and since they almost always, as the consequence, lost themselves in airy speculations.
One man only must be mentioned here by way of exception, — Aristotle, the greatest and the only truly great naturalist of antiquity and the Middle Ages, one of the grandest geniuses of all time. To what a degree he stands
ARISTOTLE ON THE ORIGIN OF LIFE. ']']
there alone, during a period of more than two thousand years, in the region of empirico-philosophical knowledge of nature, and especially in his knowledge of organic nature, is proved to us by the precious remains of his but partially surviving works. In them many traces are found of a theory of natural development. Aristotle assumes, as a matter of certainty, that spontaneous generation was the natural manner in which the lower organic creatures came into existence. He describes animals and plants originating from matter itself, through its own original force ; as, for example, moths from wool, fleas from putrid dung, wood-lice from damp wood, etc. But as the distinction of organic species, which Linnseus only arrived at two thousand years later, was unknown to him, he could form no ideas about their genealogical relations.
The fundamental notion of the theory of development, that the different species of animals and plants have been developed from a common primary species by transformation, could of course only be clearly asserted after the kinds oi species themselves had become better known, and after the extinct species had been carefully examined and compared with the living ones. This was not done until the end of the last and the beginning of the present century. It was not until the year 1801 that the great Lamarck expressed the theory of development, which he, in 1809, further elaborated in his classical " Philosophic Zoologique." While Lamarck and his countryman, Geoffroy St. Hilaire, in France, opposed Cuvier's views, and maintained a natural development of organic species by transformation and descent, Goethe and Oken at the same time pursued the same course in Germany, and helped to establish the theory
jS THE HISTORY OF CREATION.
of development. As these naturalists are generally called nature-philosophers (Naturphilosophen), and as this ambiguous designation is correct in a certain sense, it appears to me appropriate here to say a few words about the correct estimate of the " Naturphilosophie."
Although for many years in England the ideas of natural science and philosophy have been looked upon as almost equivalent, and as every truly scientific investigator of nature is most justly called there a " natural philosopher," yet in Germany for more than half a century natural science has been kept strictly distinct from philosophy, and the union of the two into a true philosophy of nature is recognized only by the few. This misapprehension is owing to the fantastic eccentricities of earlier German natural-philosophers, such as Oken, Schelling, etc. ; they believed that they were able to construct the laws of nature in their own heads, without being obliged to take their stand upon the grounds of actual experience. When the complete hollowness of their assumptions had been demonstrated, naturalists, in "the nation of thinkers," fell into the very opposite extreme, believing that they would be able to reach the high aim of science, that is, the knowledge of truth, by the mere experi- ence of the senses, and without any philosophical activity of thought.
From that time, but especially since 1830, most natiu'alists have shown a strong aversion to any general, philosophical view of nature. The real aim of natural science was now supposed to consist in the knowledge of details, and it was believed that this would be attained in the study of biology, when the forms and the phenomena of life, in all individual organisms, had become accurately known, by the help of the
OBSERVATION ANI> REFLECTION. 79
finest instruments and means of observation. It is true that among these strictly empirical, or so-called exact naturalists, there were always very many who rose above this narrow point of view, and sought the final aim in a knowledge of the general laws of organization. Yet the great majority of zoologists and botanists, during the thirty or forty years preceding Darwin, refused to concern themselves about such general laws; all they admitted was, that perhaps in the far distant future, when the end of all empiric knowledge should have been arrived at, when all individual animals and plants should have been thoroughly examined, naturalists might begin to think of discovering general biological laws.
If we consider and compare the most important advances which the human mind has made in the knowledge of truth, we shall soon see that it is always owing to philo- sophical mental operations that these advances have been made, and that the experience of the senses which certainly and necessarily precedes these operations, and the knowledge of details gained thereby, only furnish the basis for those general laws. Experience and philosophy, therefore, by no means stand in such exclusive opposition to each other as most men have hitherto supposed ; they rather necessarily supplement each other. The philosopher who is wanting in the firm foundation of sensuous experience, of empirical knowledge, is very apt to arrive at false conclusions in his general speculations, which even a moderately informed naturalist can refute at once. On the other hand, the purely empiric naturalists, who do not trouble themselves about the philosophical comprehension of their sensuous experiences, and who do not strive after genei^l knowledge, can promote science only in a very slight degree, and the chief value of
So THE HISTOPtY OF CEEATION.
their hard-won knowledge of details lies in the general results which more comprehensive minds will one day derive from them.
From a general survey of the com^se of biological develop- ment since Linngeus' time, we can easily see, as Bar has pointed out, a continual vacillation between these two ten- dencies, at one time a prevalence of the empirical — the so-called exact — and then again of the philosophical or speculative tendency. Thus at the end of the last century, in opposition to Linnaeus' purely empirical school, a natural- philosophical reaction took place, the moving spirits of which, Lamarck, Geoffroy St. Hilaire, Goethe, and Oken, endeavoured by their mental work to introduce light and order into the chaos of the accumulated empirical raw material. In opposition to the many errors and specu- lations of these natural philosophers, who went too far, Cuvier then came forward, introducing a second, purely empirical period. It reached its most one-sided development between the years 1830-1860, and there now followed a second philosophical reaction, caused by Darwin's work. Thus during the last ten years, men again have begun to endeavour to obtain a knowledge of the general laws of natiu'e, to which, after all, all detailed knowledge of experi- ence serves only as a foundation, and through which alone it acquires its true value. It is through philosophy alone that natural knowledge becomes a true science, that is, a philosophy of nature. (Gen. Morph. i. 63-108.)
Jean Lamarck and Wolfgang Goethe stand at the head of all the gTeat philosophers of nature who first established a theory of organic development, and who are the illustrious fellow-workers of Darwin. I turn first to our beloved
GOETHE AS A NATURALIST. 8 1
Goethe, who, among all, stands in the closest relations to us Germans. However, before I explain his special services to the theory of development, it seems to me necessary to say a few words about his importance as a naturalist in general, as it is commonly very little known.
I am sure most of my readers honour Goethe only as a poet and a man ; only a few have any conception of the high value of his scientific works, and of the gigantic stride with which he advanced before his own age — advanced so much that most naturalists of that time were unable to follow him. In several passages of his scientific writings he bitterly complains of the narrow-mindedness of professed naturalists, who do not know how to value his works (who cannot see the wood for the trees), and who cannot rouse themselves to discover the general laws of nature among the mass of details. He is only too just when he utters the reproach — "The philosophers will very soon discover that observers rarely rise to a stand-point from which they can survey so many important objects." It is true, at the same time, that their want of appreciation was caused by the false road into which Goethe was led in his theory of colours. This theory of colours, which he himself designates as the favourite production of his leisure, however much that is beautiful it may contain, is a complete failure in regard to its foundations. The exact mathematical method by means of which alone it is possible, in inorganic sciences, but above all in physics, to raise a structure step by step on a thoroughly firm basis, was altogether re- pugnant to Goethe. In rejecting it he allowed himself not only to be very unjust towards the most eminent phy- sicists, but to be led into errors which have greatly injured
S2 THE HISTOEY OF CPvEATlON.
the fame of his other valuable works. It is quite different in the organic sciences, in which we are but rarely able to proceed, from the beginning, upon a firm mathematical basis; we are rather compelled, by the infinitely difficult and intricate nature of the problem, at the first to form inductions — that is, we are obliged to endeavour to establish general laws by numerous individual observations, which are not quite complete. A comparison of kindred series of phenomena, or the method of combination, is here the most important instrument for inquiry, and this method was applied by Goethe with as much success as with conscious knowledge of its value, in his works relating to the philosophy of nature.
The most celebrated amongr Goethe's writinpjs relatinpf to organic nature is his Metamorphosis of Plants, which ap- peared in 1790, a work which distinctly shows a grasp of the fundamental idea of the theory of development, inasmuch as Goethe, in it, was labouring to point out a single organ, by the infinitely varied development and metamorphosis of which the whole of the endless variety of forms in the world of plants might be conceived to have arisen; this funda- mental organ he found in the leaf. If at that time the mi- croscope had been generally employed, if Goethe had examined the structure of organisms by the means of the microscope, he would have gone still fui'ther, and would have seen that the leaf is itself a compound of individual parts of a lower order, that is, of cells. He would then not have declared that the leaf, but that the cell is the real fun- damental organ by the multiplication, transformation, and combination (synthesis) of which, in the first place, the leaf is formed ; and that, in the next place, by transformation,
Goethe's theory of the skull. S^
variation, and combination of leaves there arise all the varied beauties in form and colour which we admire in the green parts, as well as in the organs of propagation, or the flowers of plants. Goethe here showed that in order to comprehend the whole of the phenomena, we must in the first place compare them, and, secondly, search for a simple type, a simple fundamental form, of which all other forms are only infinite variations.
Something similar to what he had here done for the meta- morphosis of plants he then did for the Vertebrate animals, in his celebrated vertebral theory of the skull. Goethe was the first to show, independently of Oken, who almost simultaneously arrived at the same thought, that the skull of man and of all Vertebrate animals, in particular mammals, is nothing more than a bony case, formed of the same bones, — that is, vertebras, — out of which the spine also is composed. The vertebrae of the skull are like those of the spine, bony rings lying behind each other, but in the skull are pecuHarly changed and specialized (differentiated). Although this idea has been strongly modified by recent discoveries, yet in Goethe's day it was one of the greatest advances in comparative anatomy, and was not only one of the first advances towards the understanding of the structure of Vertebrate animals, but at the same time ex- plained many individual phenomena. When two parts of a body, such as the skull and spine, which appear at first sight so different, were proved to be parts originally the same, developed out of one and the same foundation, one of the difficult problems of the philosophy of nature was solved. Here again we meet the notion of a single type — the conception of a single principle, which becomes in-
84 THE HISTORY OF CREATION.
finitely varied in the different species, and in the parts of individual species.
But Goethe did not merely endeavour to search for such far-reaching laws, he also occupied himself most actively for a long time with numerous individual researches, especially in comparative anatomy. Among these, none is perhaps more interesting than the discovery of the onidjaiv- hone in man. As this is, in several respects, of importance to the theory of development, I shall briefly explain it here. There exist in all mammals two little bones in the upper jaw, which meet in the centre of the face, below the nose, and which lie between the two halves of the real upper jawbone. These two bones, which hold the four ujjper cutting teeth, are recognized without difficulty in most mammals ; in man, however, they were at that time un- known, and celebrated comparative anatomists even laid great stress upon this want of a mid jawbone, as they con- sidered it to constitute the principal difference between men and apes — the want of a mid jawbone was, curiously enough, looked upon as the most human of all human characteristics. But Goethe could not accept the notion that man, who in all other corporeal respects was clearly only a mammal of higher development, should lack this mid jawbone.
By the general law of induction as to the mid jawbone he arrived at the special deductive conclusion that it must exist in man also, and Goethe did not rest until, after com- paring a gi'eat number of human skulls, he really found the mid jawbone. In some individuals it is preserved throughout a whole lifetime, but usually at an early age it coalesces with the neighbouring upper jawbone, and is
THEORY OF THE SKULL. 85
therefore only to be found as an independent bone in very youthful skulls. In human embryos it can now be pointed out at any moment. In man, therefore, the mid jawbone actually exists, and to Goethe the honour is due of having first firmly established this fact, so important in many respects; and this he did while opposed by the celebrated anatomist, Peter Camper, one of the most important pro- fessional authorities. The way by which Goethe succeeded in establishing this fact is especially interesting ; it is the way by which we continually advance in biological science, namely, by way of induction and deduction. Induction is the inference of a general law from the observation of numerous individual cases ; deduction, on the other hand, is an inference from this general law applied to a single case which has not yet been actually observed. From the col- lected empirical knowledge of those days, the inductive conclusion was arrived at that all mammals had mid jaw- bones. Goethe drew from this the deductive conclusion, that man, whose organization was in all other respects not essentially different from mammals, must also possess this mid jawbone ; and on close examination it was actually found. The deductive conclusion was confirmed and verified by experience.
Even these few remarks ma}^ serve to show the great value which we must ascribe to Goethe's biological re- searches. Unfortunately most of his labours devoted to this subject are so hidden in his collected works, and his most important observations and remarks so scattered in numerous individual treatises — devoted to other subjects — that it is difficult to find them out. It also sometimes happens that an excellent, truly scientific remark is so
86 THE HISTORY OF CREATION.
mucli interwoven with a mass of useless philosophical fancies, that the latter greatly detract from the former.
Nothing is perhaps more characteristic of the extraordi- nary interest which Goethe took in the investigation of organic nature than the lively way in which, even in his last years, he followed the dispute which broke out in France between Cuvier and Geofiroy de St. Hilaire. Goethe, in a special treatise which was only finished a few days before his death, in March, 1832, has given an interesting description of this remarkable dispute and its general im- portance, as well as an excellent sketch of the two great opponents. This treatise bears the title " Principes de Philosophic Zoologique par M. Geoifroy de Saint Hilaire " ; it is Goethe's last work, and forms the conclusion of the collected edition of his works. The dispute itself was, in several respects, of the highest interest. It turned essentially upon the justification of the theory of development. It was carried on, moreover, in the bosom of the French Academy, by both opponents, with a personal vehemence almost unheard of in the dignified sessions of that learned body ; this proved that both naturalists were fighting for their most sacred and deepest convictions. The conflict began on the 22nd of February, and was followed by several others ; the fiercest took place on the 19th of July, 1830. Geofiroy, as the chief of the French nature- philosophers, represented the theory of natural development and the monistic conception of nature. He maintained the mutability of organic species, the common descent of the individual species from common primary forms, and the unity of their organization — or the unity of the plan of structure, as it was then called.
GOETHE AND ST. HILAIRE. • 87
Cuvier was the most decided opponent of these views, and according to what we have seen, it could not be otherwise. He endeavoured to show that the nature- philosophers had no right to rear such comprehensive con- clusions on the basis of the empirical knowledge then possessed, and that the unity of organization — or plan of structure of organisms — as maintained by them, did not exist. He represented the teleological (dualistic) concep- tion of nature, and maintained that " the immutability of species was a necessary condition for the existence of a scientific history of nature." Cuvier had the great advan- tage over his opponent, that he was able to bring towards the proof of his assertions things obvious to the eye ; these, however, were only individual facts taken out of their con- nection with others. Geoffroy was not able to prove the higher and general connection of individual phenomena which he maintained, by equally tangible details. Hence Cuvier, in the eyes of the majority, gained the victory, and decided the defeat of the nature-philosophy and the supremacy of the strictly empiric tendency for the next thirty years.
Goethe of course supported Geoffroy's views. How deeply interested he was, even in his 81st year, in this gi'eat contest is proved by the following anecdote related by Soret : —
" Monday, Aug. 2nd, 1830. — The news of the outbreak of the revolution of July arrived in Weimar to-day, and has caused general excitement. In the course of the afternoon I went to Goethe. * Well ? ' he exclaimed as I entered, ' what do you think of this great event ? The volcano has burst forth, all is in flames, and there are no more negotia- tions behind closed doors.' * A dreadful afl^air,' I answered ;
88 THE HISTOKY OF CREATION?.
* but what else could be expected under the circum- stances, and with such a ministry, except that it would end in the expulsion of the present royal family ? ' * We do not seem to understand each other, my dear friend,^ replied Goethe. ' I am not speaking of those people at all ; I am interested in something very different, I mean the dispute between Cuvier and Geoffi'oy de Saint Hilaire, which has broken out in the Academy, and which is of such great im- portance to science.' This remark of Goethe's came upon me so unexpectedly, that I did not know what to say, and my thoughts for some minutes seemed to have come to a complete standstill. ' The affair is of the utmost import- ance,' he continued, ' and you cannot form any idea of what I felt on receiving the news of the meeting on the 19th. In Geoffroy de Saint Hilaire we have now a mighty ally for a long time to come. But I see also how great the sympathy of the French scientific world must be in this affair, for, in spite of the terrible political excitement, the meeting on the 19th was attended by a full house. The best of it is, however, that the synthetic treatment of natm^e, introduced into France by Geoffroy, can now no longer be stopped. This matter has now become public through the discussions in the Academy, carried on in the presence of a large audience; it can no longer be referred to secret committees, or be settled or suppressed behind closed doors.' "
In my book on " The General Morphology of Organisms " I have placed as headings to the difierent books and chapters a selection of the numerous interesting and important sen- tences in which Goethe clearly expresses his view of organic nature and its constant development. I will here
GOETHE ON ADAPTATION AND INHERITANCE. 89
quote a passage from the poem entitled, "The Metamor- phosis of Animals " (1819).
" All members develop themselves according to eternal laws, And the rarest form mysterionsly preserves the primitive type. Form therefore determines the animal's way of life, And in turn the way of life powerfully reacts upon all form. Thus the orderly growth of form is seen to hold Whilst yielding to change from externally acting causes." *
Here, clearly enough, the contrast between two different organic constructive forms is intimated, which are opposed to one another, and which by their inter-action determine the form of the organism ; on the one hand, a common inner original type, firmly maintaining itself, constitutes the foundation of the most different forms ; on the other hand, the externally active influence of surroundings and mode of life, which influence the original type and transform it. This Contrast is still more definitely pointed out in the following passage : —
" An inner original community forms the foundation of all organization ; the variety of forms, on the other hand, arises from the necessary relations to the outer world, and we may therefore justly assume an original difference of condi- tions, together with an uninterruptedly progressive trans- formation, in order to be able to comprehend the constancy as well as the variations of the phenomena of form."
The *' original type " which constitutes the foundation of
* Alle Glieder bilden sich aus nach ew'gen Gesetzen, TJnd die seltenste Form bewahrt im Geheimniss das Urbild. Also bestimmt die Gestalt die Lebensweise des Thieres. Und die Weise zu leben, sie wirkt auf alle Gestalten Machtig zuriick. So zeiget sich fest die geordnete Bildung, Welche zum Wechsel sich neigt durch ausserlich wirkende Wesen.
90 THE HISTORY OF CREATION.
every organic form " as the inner original community " is the inner constructive force, which receives the original direction of form-production — that is, the tendency to give rise to a particular form — and is propagated by Inheritance. The "uninterruptedly progressive transformation," on the other hand, which " springs from the necessary relations to the outer world," acting as an external formative force, produces, by Adaptation to the surrounding conditions of life, the "infinite variety of forms" (Gen. Morph. i. 154; ii. 224). The internal formative tendency of Inheritance, which retains the unity of the original type, is called by Goethe in another passage the centripetal force of the organ- ism, or its tendency to specification ; in contrast with this he calls the external formative tendency of Adaptation, which produces the variety of organic forms, the centrifugal force of organisms, or their tendency to variation. The passage in which he clearly indicates the " equilibrium " of these two extremely important organic formative tendencies, runs as follows : " The idea of metamorphosis resembles the vis centrifuga, and would lose itself in the infinite, if a counter- poise were not added to it : I mean the tendency to specifi- cation, the strong power to preserve what once has come into being, a vis centripeta, which in its deepest foundation cannot be affected by anything external."
Metamorphosis, according to Goethe, consists not merely, as the word is now generally understood, in the changes of form which the organic individual experiences during its individual development, but, in a wider sense, in the transformation of organic forms in general. His idea of metamorphosis is almost synonymous with the theory of development. This is clear, among other things, from the
Goethe's speculations. 91
following passage : — " The triumph of physiological meta- morphosis manifests itself where the whole separates and transforms itself into families, the families into genera, the genera into species, and then again into other varieties down to the individual. This operation of nature goes on ad infinitum ; she cannot rest inactive, but neither can she keep and preserve all that she has produced. From seeds there are always developed varying plants, exhibiting the relations of their parts to one another in an altered manner."
Goethe had, in truth, discovered two great mechanical forces of nature, which are the active causes of organic formations, his two organic formative tendencies — on the one hand the conservative, centripetal, and internal forma- tive tendency of Inheritance or specification ; and on the other hand the progressive, centrifugal, and external form- ative tendency of Adaptation, or metamorphosis. This profound biological intuition could not but lead him natur- ally to the fundamental idea of the Doctrine of Filiation, that is, to the conception that the organic species resembling one another in form are actually related by blood, and that they are descended from a common original type. In regard to the most important of all animal groups, namely that ot Vertebrate animals, Goethe expresses this doctrine in the following passage (1796 ) : — " Thus much then we have gained, that we may assert without hesitation that all the more perfect organic natures, such as fishes, amphibious animals, birds, mammals, and man at the head of the last, were all formed upon one original type, which only varies more or less in parts which are none the less permanent, and still daily changes and modifies its form by propagation."
This sentence is of interest in more than one way. The
92 THE HISTORY OF CREATION.
theory that all " the more perfect organic natures," that is all Vertebrate animals, are descended from one common prototype, that they have arisen from it by propagation (Inheritance) and transformation (Adaptation), may be distinctly inferred. But it is especially interesting to observe that Goethe admits no exceptional position for man, but rather expressly includes him in the tribe of the other Vertebrate animals. The most important special inference of the Doctrine of Filiation, that man is descended from other Vertebrate animals, may here be recognized in the germ.^
This exceedingly important ftmdamental idea is expressed by Goethe still more clearly in another passage (1807), in the following words : — " If we consider plants and animals in their most imperfect condition, they can scarcely be distin- guished. But this much we can say, that the creatures which by degrees emerge as plants and animals out of a common phase, where they are barely distinguishable, anive at perfection in two opposite directions ; so that the plant in the end reaches its highest glory in the tree, which is immovable and stiff, the animal in man, who possesses the greatest elasticity and freedom." This remarkable passage not only indicates most explicitly the genealogical relationship between the vegetable and animal kingdoms, but contains the germ of the monophyletic hypothesis of descent, the importance of which I shall have to explain hereafter. (Compare Chapter XVI. and the Pedigree, p. 898.)
At the time when Goethe in this way sketched the fundamental features of the Theory of Descent, another German philosopher, Gottfried Reinhold Treviranus, of
TEEVIRANUS, THE FIRST NATUEE-PHILOSOPHEE. 93
Bremen (born 1776, died 1837), was zealously engaged at the same work. As Wilhelm Focke has recently shown, Treviranus, even in the earliest of his greater works, " The Biology or Philosophy of Animate Nature," which appeared at the beginning of the present century, had already developed monistic views of the unity of nature, and of the genealogical connection of the species of organisms, which entirely correspond with our present view of the matter. In the first three volumes of the Biology, which appeared succes- sively in 1802, 1803, and 1805 (therefore several years before Oken's and Lamarck's principal works), we find numerous passages which are of interest in this respect. I shall here quote only a few of the most important.
In speaking of the principal question of our theory, the question of the origin of organic species, Treviranus makes the following remarks : — " Every form of life can be produced by physical forces in one of two ways : either by coming into being out of formless matter, or by modification of an already existing form by a continued process of shaping. In the latter case the cause of this modification may lie either in the influence of a dissimilar male genera- tive matter upon the female germ, or in the influence of other powers which operate only after procreation. In every living being there exists the capability of an endless variety of form-assumption ; each possesses the power to adapt its organization to the changes of the outer world, and it is this power put into action by the change of the universe that has raised the simple zoophytes of the primitive world to continually higher stages of organization, and has introduced a countless variety of species into animate nature."
By zoophytes, Treviranus here means organisms of the
94 THE HISTORY OF CREATION.
lowest order and of the simplest character, namely, those neutral primitive beings which stand midway between animals and plants, and on the whole correspond with our protista. " These zoophytes," he remarks in another pass- age, "are the original forms out of which all the organisms of the higher classes have arisen by gradual development. We are further of opinion that every species, as well as every individual, has certain periods of growth, of bloom, and of decay, but that the decay of a species is degeneration, not dissolution, as in the case of the individual. From this it appears to us to follow that it was not the great catastrophes of the earth" (as is generally supposed) which destroyed the animals of the primitive world, but that many survived them, and it is more probable that they have disappeared from existing nature, because the species to which they belonged have completed the circle of their existence, and have become changed into other kinds."
When Treviranus, in this and other passages, points to degeneration as the most important cause of the transforma- tion of the animal and vegetable species, he does not under- stand by it what is now commonly called degeneration. With him "degeneration" is exactly what we now call Adaptation or modification, by the action of external formative forces. That Treviranus explained this trans- transformation of organic species by Adaptation, and its preservation by Inheritance, and thus the whole variety of organic forms by the inter-action of Adaptation and In- heritance, is clear also from several other passages. How profoundly he grasped the mutual dependence of all living creatures on one another, and in general the universal connection between cause and effect — that is, the monistic
TEEVIRANUS ON SOLIDARITY. 95
causal connection between all members and parts of the universe — is further shown, among others, by the following remarks in his Biology : — " The living individual is depen- dent upon the species, the species upon the fauna, the fauna upon the whole of animate nature, and the latter upon the organism of the earth. The individual possesses indeed a peculiar life, and so far forms its own world. But just because its life is limited it constitutes at the same time an organ in the general organism. Every living body exists in consequence of the universe, but the universe, on the other hand, exists in consequence of it."
It is self-evident that so profound and clear a thinker as Treviranus, in accordance with this grand mechanical con- ception of the universe, could not admit for man a privileged and exceptional position in nature, but assumed his gradual development from lower animal forms. And it is equally self-evident, on the other hand, that he did not admit a chasm between organic and inorganic nature, but main- tained the absolute unity of the organization of the whole universe. This is specially attested by the following sentence : — " Every inquiry into the influence of the whole of nature on the living world must start from the principle, that all living forms are products of physical influences, which are acting even now, and are changed only in degree, or in their direction." Hereby, as Treviranus himself says, " The fundamental problem of biology is solved," and we add, solved in a purely mechanical or monistic sense.
Neither Treviranus nor Goethe is commonly considered the most eminent of the German nature-philosophers, but Lorenz Oken, who, in establishing the vertebral theory of the skull, came forward as a rival to Goethe, and did not
96 THE HISTORY OF CREATION.
entertain a very kindly feeling towards him. Altliough they lived for some time in the same neighbourhood, yet the natures of these two men were so very different, that they could not well be drawn towards each other. Oken's " Manual of the Philosophy of Nature," which may be designated as the most important production of the nature-philosophy school then existing in Germany, appeared in 1809, the same year in which Lamarck's fundamental work, the " Philosophic Zoologique," was published. As early as 1802, Oken had published an " Outline of the Philosophy of Nature." As we have already intimated, in Oken's as in Goethe's works, a number of valuable and profound thoughts are hidden among a mass of erroneous, very eccentric, and fantastic con- ceptions. Some of these ideas have only quite recently and gradually become recognized in science, many years after they were first expressed. I shall here quote only two thoughts, which are almost prophetic, and which at the same time stand in the closest relation to the theory of development.
One of the most important of Oken's theories, which was formerly very much decried, and was most strongly com- batted, especially by the so-called " exact experimentalists," is the idea that the phenomena of life in all organisms pro- ceed from a common chemical substance, so to say, from a general simple vitcd-suhstance, which he designated by the name Ursclileim, or original slime. By it he meant, as the name indicates, a mucilaginous substance, an albuminous combination, which exists in a semi-fluid condition of aggre- gation, and possesses the power, by adaptation to different conditions of existence in the outer world and by inter- action with its material, of producing the most various forms
OKENS THEORIES. 97
I^ow, we need only change the expression ''original slime" (Urschleim) into Protojplasmi, or cell-suhstance, in order to arrive at one of the grandest results which we owe to microscopic investigations during the last ten years, more especially to those of Max Schultze. By these investigations it has been shown that in all living^ bodies, without ex- ception, there exists a certain quantity of mucilaginous albu- minous matter, in a semi-fluid condition; and that this nitrogen-holding carbon-compound is exclusively the ori- ginal seat and agent of all the phenomena of life, and of all production of organic forms. All other substances which appear in the organism, besides these, are either formed by this active matter of life, or have been introduced from with- out. The organic egg, the original cell out of which every animal and plant is first developed, consists essentially only of one round little lump of such albuminous matter. Even the yolk of an egg is nothing but albumen, mixed with granules of fat. Oken was therefore right when, more divining than knowing, he made the assertion — "Every organic thing has arisen out of slime, and is nothing but slime in different forms. This primitive slime originated in the sea, from inorganic matter in the course of planetary- evolution."
Another equally grand idea of the same philosopher is closely connected with his theory of primitive slime, which coincides with the extremely important Protoplasm theoru Eor Oken, as early as 1809, asserted that the primitive slime produced in the sea by spontaneous generation, at once assumed the form of microscopically small bladders, which he called " Mile'' or " Infusoria!' " Organic nature has for its basis an infinity of such vesicles." These little
98 THE HISTOHY OF CEEATION.
bladders arise from original semi-fluid globules of the primi- tive slime, by the fact of their periphery becoming con- densed. The simplest organism, as well as every animal and every plant of higher kind, is nothing else than " an accu- mulation (synthesis) of such infusorial bladders, which by various combinations assume various forms, and thus develop into higher organisms." Here again we need only translate the expression little bladder, or infusorium, by the word cell, and we arrive at the Cell theory, one of the grandest biological theories of our century. Schleiden and Schwann, about thirty years ago, were the first to furnish experiential proof that all organisms are either simple cells, or accumulations (syntheses) of such cells, and the more recent protoplasm theory has shown that protoplasm (the original slime) is the most essential (and sometimes the only) con- stituent part of the genuine cell. The properties which Oken ascribes to his Infusoria are exactly the properties of cells, the properties of elementary beings, by whose accumulation, combination, and varying development, the higher organisms are formed.
These two extremely fruitful thoughts of Oken, on account of the absurd form in which he expressed them, were at first little heeded, or entirely misunderstood, and it was re- served for a much later era to establish them by actual observation. The supposition that the individual species of plants and animals originated from common prototypes by a slow and gTadual development of the higher organisms out of lower ones, was of course most closely connected with these ideas. Man's descent from lower organisms was like- wise asserted by Oken — " Man has been developed, not created." Although many arbitrary perversities and ex-
THE NATUH-PHILOSOPHIE. 99
travagant fancies may be found in Oken's philosophy of nature, they must not prevent us paying our just admira- tion to these grand ideas, which were so far in advance of their age. This much is clearly evident from the statements of Goethe and Oken which we have quoted, and from the views of Lamarck and Geoffroy which have to be discussed next, that during the first decade of our century no doctrine approached so nearly to the natural Theory of Descent, newly established by Darwin, as the much decried " Natxir-philosophie."
lOO - THE HISTORY OF CKEATION.
CHAPTER V.
THEORY OF DEYELOPMENT ACCORDING TO KANT
AND LAMARCK.
Kant's Dnalistic Biology. — His Conception of tlie Origin of Inorganic Nature by Mechanical Causes, of Organic Nature by Causes acting for a Definite Purpose. — Contradiction of this Conception with his leaning towards the Theory of Descent. — Kant's Genealogical Theory of Development. — Its Limitation by his Teleology. — Comparison of Genealogical Biology with Comparative Philology. — Views in favour of the Theory of Descent entertained by Leopold Buch, Bar, Schleiden, Unger, Schaafhausen, Victor Cams, Biichncr. — French Nature, philosophy. — Lamarck's Philosophic Zoologique. — Lamarck's Monistic (mechanical) System of Nature. — His Views of the Inter-action of the Two Organic Formative Tendencies of Inheritance and Adaptation. — Lamarck's Conception of Man's Development from Ape-like Mammals. — Geoffroy St. Hilaire's, Naudin's, and Lecoq's Defence of the Theory of Descent. — English Nature-philosophy. — Views in favour of the Theory of Descent, entertained by Erasmus Darwin, W. Herbert, Grant, Freke, Herbert Spencer, Hooker, Huxley. — The Double Merit of Charles Dar^vin.
The teleological view of nature, wliich explains the plie- nomena of the organic world by the action of a personal Creator acting for a definite purpose, necessarily leads, when carried to its extreme consequences, either to utterly unten- able contradictions, or to a twofold (dualistic) conception of nature, which most directly contradicts the unity and simplicity of the supreme laws which are everywhere perceptible. The philosophers who embrace teleology must
K ant's biological theories. to I
necessarily assume two fundamentally different natures : an inorganic nature, wliich must be explained by causes acting mechanically (causae efficientes), and an organic nature, which must be explained by causes acting for a definite purpose (causae finales). (Compare p. 34.)
This dualism meets us in a striking manner when con- sidering the conceptions of nature formed by Kant, one of the greatest German philosophers, and his ideas of the com- ing into being of organisms. A closer examination of these ideas is forced upon us here, because in Kant we honour one of the few philosophers who combine a solid scientific cul- ture with an extraordinary clearness and profundity of speculation. The Konigsberg philosopher gained the highest celebrity, not only among speculative philosophers as the founder of critical philosophy, but acquired a brilliant name also among naturalists by his mechanical cosmogeny. Even in the year 1755, in his " General History of Nature, and Theory of the Heavens," ^ he made the bold attempt " to discuss the constitution and the mechanical origin of the whole universe, according to Newton's principles," and to explain them mechanically by the natural course of develop- ment, to the exclusion of all miracles. This cosmogeny of Kant, or " cosmological gas theory," which we shall briefly discuss in a future chapter, was at a later day fully estab- lished by the French mathematician Laplace and the Eng- lish astronomer Herschel, and enjoys at the present day almost universal recognition. On account of this import- ant work alone, in which exact knowledge is co^upled with most profound speculation, Kant deserves the honour- able name of a natural philosopher in the best and purest
sense of the word. 6
I02 THE HISTORY OF CREATION.
If we read Kant's Criticism of the Teleological Faculty of Judgment, his most important biological work, we perceive that in contemplating organic nature he always maintains what is essentially the teleological or dualistic point of view ; whilst for inorganic nature he, uncondition- ally and without reserve, assumes the mechanical or monis- tic method of explanation. He affirms that in the domain of inorganic nature all the phenomena can be explained by mechanical causes, by the moving forces of matter itself, but not so in the domain of organic nature. In the whole of Anorganology (in Geology and Mineralogy, in Meteorology and Astronomy, in the physics and chemistry of inorganic natural bodies), all phenomena are said to be explicable merely by 'mechanism (causa efficiens), without the interven- tion of a final purpose. In the whole domain of Biology, on the other hand — in Botany, Zoology, and Anthropology — me- chanism is not considered sufficient to explain to us all their phenomena ; but we are supposed to be able to comprehend them only by an assumption of 2, final cause acting for a defi- nite purpose (causa finahs). In several passages Kant em- phatically remarks that, from a strictly scientific point of view, all phenomena, without exception, require a mechani- cal interpretation, and that mechanism alone can offer a true exi^lanation. But at the same time he thinks, that in regard to living natural bodies, animals and plants, our human power of comprehension is limited, and not sufficient for arriving at the real cause of organic processes, especially at the origin of organic forms. The right of human reason to explain all phenomena mechanically is unlimited, he says, but its poiuer is limited by the fact that organic nature can be conceived only from a teleological point of view.
KANTS BIOLOGICAL THEORIES. IO3
Some passages are, however, very remarkable, in which Kant in a surprising manner deviates from this mode of viewing things, and expresses, more or less distinctly, the fundamental idea of the Theory of Descent. He even as- serts the necessity of a genealogical conception of the series of organisms, if we at all wish to understand it scien- tifically. The most important and remarkable of these pas- sages occurs in his " Methodical System of the Teleological Faculty of Judgment " (§ 79), which appeared in 1790 in the " Criticism of the Faculty of Judgment." Considering the extraordinary interest which this passage possesses, both for forming a correct estimate of Kant's philosophy, as well as for the Theory of Descent, I shall here insert it verhatim.
" It is desirable to examine the great domain of organized nature by means of a methodical comparative anatomy, in order to discover whether we may not find in it something resembling a system, and that too in connection with the mode of generation, so that we may no longer be compelled to stop short with a mere consideration of forms as they are — which gives us no insight into their generation — and need no longer give up in despair all hope of gaining a full insight into this department of nature. The agreement of so many kinds of animals in a certain common plan of structure, which seems to be visible not only in their skeletons, but also in the arrangement of the remaining parts — so that a wonderfully simple typical form, by the shortening and lengthening of some parts, and by the suppression and development of others, might be able to produce an immense variety of species — gives us a ray of hope, though feeble, that here perhaps some result may be obtained, by the application of the principle of the mechanism of nature, without which.
104 THE HISTORY OF CREATION.
in fact, no science can exist. This analogy of forms (in so far as they seem to have been produced in accordance with a common prototype, notwithstanding their great variety) strengthens the supposition that they have an actual blood- relationship, due to origination from a common parent; a supposition which is arrived at by observation of the graduated approximation of one class of animals to another, beginning with the one in which the principle of purposive- ness seems to be most conspicuous, that is man, and extend- ing down to the polyps, and from these even down to mosses and lichens, and arriving finally at raw matter, the lowest stage of nature observable by us. From this matter and its forces the whole apparatus of Nature seems to have descended according to mechanical laws (such as those which she follows in the production of crystals) ; yet this apparatus, as seen in organic beings, is so incomprehensible to us, that we feel ourselves compelled to conceive for it a different principle. But it would seem that the archaeologist of Nature is at liberty to regard the great Family of creatures (for as a Family we must conceive it, if the above- mentioned continuous and connected relationship has a real foundation) as having sprung from the immediate results of her earliest revolutions, judging from all the laws of their mechanism known to or conjectured by him."
If we take this remarkable passage out of Kant's " Criticism of the Teleological Faculty of Judgment," and consider it by itself, we cannot but be astonished to find how profoundly and clearly the great thinker, even in 1790, had recognized the inevitable necessity of the Doctrine of Descent, and designated it as the only possible way of explaining organic nature by mechanical laws — that is, by
KANT AS A TELEOLOGIST. I05
true scientific reasoning. On account of tliis one passage taken by itself, we might place Kant beside Goethe and Lamarck, as one of the first founders of the Doctrine of Descent ; and considering the high authority which Kant's Critical Philosophy most justly enjoys, this circumstance might perhaps induce many a philosopher to decide in favour of the theory. But as soon as we consider this passage in connection with the other train of thoughts in the " Criticism of the Faculty of Judgment," and balance it against other directly contradictory passages, we see clearly that Kant, in these and some similar (but weaker) sentences, went beyond himself, and abandoned the teleo- logical point of view which he usually adopts in Biology.
Directly after the admirable passage which I have just quoted, there follows a remark which completely takes off its edge. After having quite correctly maintained the origin of organic forms out of raw matter by mechanical laws (in the manner of crystallization), as well as a gTadual development of the different species by descent from one common original parent, Kant adds, " But he (the archseolo- gist of nature, that is the palseontologist) must for this end ascribe to the common mother an organization ordained purposely with a view to the needs of all her offspring, otherwise the possibility of suitability of form in the pro- ducts of the animal and vegetable kingdoms (i.e. teleological adaptation) cannot be conceived at all." This addition clearly contradicts the most important fundamental thought of the preceding passage, viz. that a purely mechanical ex- planation of organic nature becomes possible through the Theory of Descent. And that the teleological conception of organic nature predominated with Kant, is shown by
I06 THE HISTOEY OF CREATION.
the heading of the remarkable § 79, which contains the two contradictory passages cited : " Of the Necessary Suhordinar- tion of the Mechanical to the Teleological FrineiiDle, in the explanation of a thing as a lourpose or object of Nature."
He expresses himself most decidedly against the mechanical explanation of organic nature in the following passage (§ 74) : "It is quite certain that we cannot become sufficiently acquainted with organized creatures and their hidden potentialities by aid of purely mechanical natural principles, much less can we explain them ; and this is so certain, that we may boldly assert that it is absurd for man even to con- ceive such an idea, or to hope that a Newton may one day arise able to make the production of a blade of grass com- prehensible, according to natural laws ordained by no inten- tion; such an insight we must absolutely deny to man." Now, however, this impossible Newton has really appeared seventy years later in Darwin, whose Theory of Selection has actually solved the problem, the solution of which Kant had considered absolutely inconceivable !
In connection with Kant and the German philosoj^hers whose theories of development have already occupied us in the preceding chapter, it seems justifiable to consider briefly some other German naturalists and philosophers, who, in the course of our century, have more or less distinctly resisted the prevailing teleological views of creation, and vindicated the mechanical conception of things which is the basis of the Doctrine of Filiation. Sometimes general philosophical considerations, sometimes special emj^irical observations, were the motives which led these thinking men to form the idea that the various individiial species of organisms must have originated from common primary forms. Among them
LEOPOLD BUCH. IO7
I must first mention tlie great German geologist, Leopold Buch. Important observations as to the geographical dis- tribution of plants led him to the following remarkable assertion in his excellent "Physical Description of the Canary Islands " : —
"The individuals of genera, on continents, spread and widely diffuse themselves, and by the difference of localities, nourishment, and soil, form varieties ; and being in conse- quence of their isolation never crossed by other varieties, and so brought back to the main type, they in the end become a permanent and a distinct species. Then, perhaps, in other ways, they once more become associated with other descendants of the original form — which have likewise become new varieties — and both now appear as very distinct species, no longer mingling with one another. Not so on islands. Being commonly confined in narrow valleys or within the limit of small zones, individuals can reach one another and destroy every commencing production of a per- manent variety. Much in the same way the peculiarities or faults in language, originating with the head of some family, become, through the extension of the family, indigenous throughout a whole district. If the district is separated and isolated, and if the language is not brought back to its former purity by constant connection with that spoken in neighbouring districts, a dialect will be the result. If natural obstacles, forests, constitution, form of government, unite the inhabitants of the separate district still more closely, and separate them still more completely from their neigh- bours, the dialect is fixed, and becomes a completely distinct language." (Uebersicht der Flora auf den Canarien,
a 133.)
i
1 08 THE HISTORY OF CREATION.
We perceive that Bueli is here led to the fundamental idea of the Theory of Descent by the phenomena of the geography of plants, a department of biological knowledge which in fact furnishes a mass of proofs in favour of it. Darwin has minutely discussed these proofs in two separate chapters of his book (the 11th and 12th). Buch's remark is further of interest, because it leads us to the exceedingly instructive comparison of the different branches of language with the species of organisms, a comparison which is of the greatest use to Comparative Philology, as well as to Compara- tive Botany and Zoology. Just as, for example, the different dialects, provincialisms, branches, and off-shoots of the German, Slavonic, Greco-Latin, and Irano-Indian parent lan- guage, are derived from a single common Indo- Germanic parent tongue, and just as their differences are explained by Adaptation, and their common fundamental characters ex- plained hy Inheritance, so in like manner the different species, genera, families, orders, and classes of Vertebrate animals are derived from a single common vertebrate form of animal. Here also Adaptation is the cause of differences, Inheritance the cause of community of character. This interesting parallelism in the divergent development of the forms of speech and the forms of organisms has been discussed in the clearest manner by one of our first comparative philolo- gists, the talented Augustus Schleicher, whose premature death, four years ago, remains an irreparable loss, not only to our University of Jena, but to the whole of monistic science.^
Among other eminent German naturalists who have ex- pressed their belief in the Theory of Descent more or less distinctly, arriving at their conclusion in very various ways.
BAR, SCHLEIDEN, UNGER. IO9
I must next mention Carl Ernst Bar, the great reformer of animal embryology. In a lecture delivered in 1834, entitled " The Most General Laws of Nature in All Development," he shows, in the clearest way, that only in a very childish view of nature could organic species be regarded as perma- nent and unchangeable types, and that really they can be only passing series of generations, which have developed by transformation from a common original form. The same conception again received firm support from Baer, in 1859, through a consideration of the of laws the geographical distribution of organisms.
J. M. Schleiden, who founded, thirty years ago, in Jena, a new epoch in Botany by his strictly empirico-philosophical and truly scientific method, illustrated the philosophical significance of the conception of organic species in his inci- sive " Outlines of Scientific Botany," "^ and showed that it had only a subjective origin in the general law of sjpecifica- tion. The difierent species of plants are only the specified productions of the formative tendencies of plants, which arise from the various combinations of the fundamental forces of organic matter.
The eminent botanist, F. Unger, of Vienna, was led by his profound and comprehensive investigations on extinct vegetable species, to a palseontological history of the de- velopment of the vegetable kingdom, which distinctly asserts the principle of the Theory of Descent. In his " Attempt at a History of the World of Plants " (1852), he maintains the derivation of all different species of plants from a few primary forms, and perhaps from a single