The History of Creation, Vol. 1 (of 2)
by Ernst Haeckel · English · Gutenberg #40472 · 700,496 chars · public domain (US)
The Project Gutenberg eBook of The History of Creation, Vol. 1 (of 2)
This eBook is for the use of anyone anywhere in the United States and
most other parts of the world at no cost and with almost no restrictions
whatsoever. You may copy it, give it away or re-use it under the terms
of the Project Gutenberg License included with this eBook or online
at www.gutenberg.org. If you are not located in the United States,
you will have to check the laws of the country where you are located
before using this eBook.
Title: The History of Creation, Vol. 1 (of 2)
Author: Ernst Haeckel
Editor: Sir E. Ray Lankester
Translator: L. Dora Schmitz
Release date: August 14, 2012 [eBook #40472]
Most recently updated: October 23, 2024
Language: English
Other information and formats: www.gutenberg.org/ebooks/40472
Credits: Produced by Adrian Mastronardi, Turgut Dincer, Jason Palmer
and the Online Distributed Proofreading Team at
http://www.pgdp.net (This file was produced from images
generously made available by The Internet Archive)
*** START OF THE PROJECT GUTENBERG EBOOK THE HISTORY OF CREATION, VOL. 1 (OF 2) ***
+------------------------------------------------------------------+
| Transcriber’s note: |
| |
| This book was published in two volumes, of which this is the |
| first. The second volume was released as Project Gutenberg ebook |
| #40473, available at https://www.gutenberg.org/ebooks/40473 |
| |
| Numbers enclosed in square brackets, e.g. [1], relate to |
| footnotes, which have been placed at the end of the text. |
| Numbers enclosed in parentheses, e.g. (1), relate to works |
| referred to in the text and listed at the end of volume II. |
| |
| In the text versions of these two volumes, words in _italics_ |
| are enclosed in underscores, +bold+ words are enclosed in plus |
| signs, and words in =Gothic script= are enclosed in equal signs. |
| Curly brackets are used to represent subscripts, e.g. k{1}. |
+------------------------------------------------------------------+
THE HISTORY OF CREATION.
[Illustration: Development of a Calcareous Sponge (Olynthus).]
THE
HISTORY OF CREATION:
_OR THE DEVELOPMENT OF THE EARTH AND ITS
INHABITANTS BY THE ACTION OF NATURAL CAUSES._
A POPULAR EXPOSITION OF
THE DOCTRINE OF EVOLUTION IN GENERAL, AND OF THAT OF
DARWIN, GOETHE, AND LAMARCK IN PARTICULAR.
FROM THE GERMAN OF
ERNST HAECKEL,
PROFESSOR IN THE UNIVERSITY OF JENA.
THE TRANSLATION REVISED BY
E. RAY LANKESTER, M.A., FELLOW OF EXETER COLLEGE, OXFORD.
_IN TWO VOLUMES._
VOL. I.
NEW YORK:
D. APPLETON AND COMPANY,
1, 3, AND 5 BOND STREET.
1880.
A sense sublime
Of something 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;
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 stars
Of azure heaven, the unenduring clouds,
In flower and tree, in every pebbly stone
That paves the brooks, the stationary rocks,
The moving waters and the invisible air.
WORDSWORTH.
CONTENTS OF VOL. I.
CHAPTER I.
NATURE AND IMPORTANCE OF THE DOCTRINE OF FILIATION,
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.—Knowledge and
Belief.—History of Creation and History of
Development.—The Connection between the History of
Individual and Palæontological 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 1
CHAPTER II.
SCIENTIFIC JUSTIFICATION OF THE THEORY OF DESCENT.
HISTORY OF CREATION ACCORDING TO LINNÆUS.
The Theory of Descent, or Doctrine of Filiation, as the
Monistic Explanation 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, _à posteriori_.—Transition of _à posteriori_
knowledge, by inheritance, into _à priori_
knowledge.—Contrast between the Supernatural Hypotheses
of the Creation according to Linnæus, 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.—Linnæus as the
Founder of the Systematic Description of Nature and
Distinction of Species.—Linnæus’ Classification and
Binary Nomenclature.—Meaning of Linnæus’ Idea of
Species.—His History of Creation.—Linnæus’ view of the
Origin of Species 24
CHAPTER III.
THE HISTORY OF CREATION ACCORDING TO CUVIER
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 Four Principal
Forms (types or branches) of the Animal Kingdom, by Cuvier
and Bär.—Cuvier’s Services to Palæontology.—His
Hypothesis of the Revolutions of our Globe, and the Epochs
of Creation separated by them.—Unknown Supernatural
Causes of the Revolutions, 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.—Rude Conception of the Creator as a
man-like being in Agassiz’s Hypothesis of Creation.—Its
internal Inconsistency and Contradictions with the
important Palæontological Laws discovered by Agassiz 47
CHAPTER IV.
THEORY OF DEVELOPMENT ACCORDING TO GOETHE
AND OKEN.
Scientific Insufficiency 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 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 Views of the Common Descent of all
Vertebrate Animals, including Man.—Theory of Development
according to Gottfried Reinhold 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 OF DEVELOPMENT ACCORDING TO KANT AND
LAMARCK.
Kant’s Dualistic Biology.—His Conception of the 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, Bär,
Schleiden, Unger, Schaafhausen, Victor Carus,
Büchner.—French Nature-philosophy.—Lamarck’s Philosophic
Zoologique.—Lamarck’s Monistic (mechanical) System of
Nature.—His Views of the Interaction 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 Darwin 100
CHAPTER VI.
THEORY OF DEVELOPMENT ACCORDING TO LYELL
AND DARWIN.
Charles Lyell’s Principles of Geology.—His Natural
History of the Earth’s Development.—Origin of the
Greatest Effects through the Multiplication of the
Smallest Causes.—Unlimited Extent of Geological
Periods.—Lyell’s Refutation of Cuvier’s History of
Creation.—The Establishment of the Uninterrupted
Connection of Historical Development by Lyell and
Darwin.—Biographical Notice of Charles Darwin.—His
Scientific Works.—His Theory of Coral
Reefs.—Development 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 Cultivated
Organisms.—Darwin’s Study of Domestic
Pigeons.—Importance of Pigeon Breeding.—Common Descent
of all Races of Pigeons 125
CHAPTER VII.
THE THEORY OF SELECTION (DARWINISM).
Darwinism (Theory of Selection) and Lamarckism (Theory of
Descent).—The Process of Artificial Breeding.—Selection
of the Different Individuals for After-breeding.—The
Active Causes of Transmutation.—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 Struggle for Existence, or Competition
to attain the Necessaries of Life.—Transforming Force of
the Struggle for Existence.—Comparison of Natural and
Artificial Breeding.—Selection in the Life of
Man.—Military and Medical Selection 149
CHAPTER VIII.
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 Propagation.—Spontaneous Generation and
Propagation.—Non-sexual or Monogonous
Propagation.—Propagation by Self-Division.—Monera and
Amœba.—Propagation by the formation of Buds, by the
formation of Germ-Buds, by the formation of
Germ-Cells.—Sexual or Amphigonous Propagation.—Formation
of Hermaphrodites.—Distinction of Sexes, or
Gonochorism.—Virginal Breeding, or
Parthenogenesis.—Material Transmission of Peculiarities
of both Parents to the Child by Sexual
Propagation.—Difference between Transmission by
Inheritance in Sexual and in Asexual Propagation 175
CHAPTER IX.
LAWS OF TRANSMISSION BY INHERITANCE. ADAPTATION AND
NUTRITION.
Distinction between Conservative and Progressive
Transmission by Inheritance.—Laws of Conservative
Transmission: Transmission of Inherited
Characters.—Uninterrupted or Continuous
Transmission.—Interrupted or Latent
Transmission.—Alternation of
Generations.—Relapse.—Degeneracy.—Sexual
Transmission.—Secondary Sexual Characters.—Mixed or
Amphigonous Transmission.—Hybrids.—Abridged or
Simplified Transmission.—Laws of Progressive Inheritance:
Transmission of Acquired Characters.—Adapted or Acquired
Transmission.—Fixed or Established
Transmission.—Homochronous Transmission (Identity in
Epoch).—Homotopic Transmission (Identity in
Part).—Adaptation and Mutability.—Connection between
Adaptation and Nutrition.—Distinction between Indirect
and Direct Adaptation 203
CHAPTER X.
LAWS OF 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 Existence and Cumulative Counter-Influence of the
Organism.—Free Will.—Use and Non-use of
Organs.—Practice and Habit.—Correlative
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
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 Existence, or Competition for the
Necessaries of Life.—Disproportion between the Number of
Possible or Potential, and the Number of Real or Actual
Individuals.—Complicated Correlations of all Neighbouring
Organisms.—Mode of Action in Natural
Selection.—Homochromic 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, Differentiation,
Divergence of Characters).—Transition of Varieties into
Species.—Idea of Species.—Hybridism.—Law of Progress or
Perfecting (Progresses, 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 Fructification 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 Development 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.Stereometrical Fundamental Forms of Crystals and
of Organisms.—Organic and Inorganic Forces.—Vital
Force.—Growth and Adaptation 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
Structural-Units.—Cytods and Cells.—Four Different Kinds
of Plastids 316
CHAPTER XIV.
MIGRATION 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.—Continual Change of the Area of
Distribution by Elevations and Depressions of the
Ground.—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 Theory of
Descent 350
LIST OF ILLUSTRATIONS.
PLATES.
PAGE
Development of a Calcareous Sponge (Olynthus) _Frontispiece_
I.—Life History of a Simplest Organism _To face page_ 184
II., III.—Germs or Embryos of Four Vertebrates ” 306
FIGURES.
1.—Propagation of Moneron 186
2.—Propagation of Amœba 188
3.—Egg of Mammal 189
4.—First Development of Mammal’s Egg 190
5.—The Human Egg Enlarged 297
6.—Development of Mammal’s Egg 299
7.—Embryo of a Mammal or Bird 304
AUTHOR’S PREFACE 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 Morphologie,” 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 effected in all biological science by his
reform of the Descent Theory and its establishment through the doctrine
of selection. At the same time, in the “Generelle Morphologie,” 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 hypothetical
pedigrees for the various species of organisms.
The “Generelle Morphologie” 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 the “Natürliche Schöpfungsgeschichte” in
Germany. This book took its origin in the shorthand notes of a course of
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 bringing 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 sufficiently 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 ontogeny, palæontology
and taxonomy, chorology and œcology, 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 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 contradistinction 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 monograph,
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 organisation, because in it the
morphological conditions possess a greatly superior, and the
physiological conditions an inferior, import, and because all species of
Calcispongiæ are remarkable 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 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 Calcareous 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 may draw up, in addition to this, another systematic arrangement
(more nearly agreeing with the arrangement of the Calcispongiæ 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 arranging 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 individual systematist. In truth, from the point
of view of the theory of descent, it appears altogether an unimportant
question as to whether we give a wider or a narrower signification 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 by systematists, not only as belonging to different
species, but even to different genera. Fig. 10 in the frontispiece
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 Monograph. 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
consequences 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 in the “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.”
ERNST HEINRICH HAECKEL.
_Jena, June 24th, 1873._
NOTE.
Feeling sure that such a book as Professor Haeckel’s
“Schöpfungsgeschichte” 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 undertook 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 rendering 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 objection 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. R. L.
_Oxford, October, 1874._
THE HISTORY OF CREATION.
CHAPTER I.
NATURE AND IMPORTANCE OF THE DOCTRINE OF FILIATION, OR DESCENT-THEORY.
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.—Knowledge and
Belief.—History of Creation and History of
Development.—The Connection between the History of
Individual and Palæontological 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,”(1) has, within this short period, assumed
dimensions 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 Theory of Development,
which embraces in its vast range the whole domain of human knowledge.
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 immensely 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 modern science upon practical
life, still it must, estimated from a higher 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.
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 Darwin. 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 contradictions, 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 published 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 zoological, 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 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
organisms_ (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 forms, and that they have
developed themselves 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 naturalists, and especially by
Lamarck and Goethe, in the beginning of our century, still it was
through Darwin, thirteen years ago, that it received its complete
demonstration and causal 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 _mechanical 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 condition of
aggregation, which are always wanting in the Anorgana. Upon this
important distinction rests the division 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 explaining to us 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-miraculous history of the development 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 first 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 his work, “On the Origin of
Species,” not a word is found 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 opposition 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 Relation to Sex,” that
Darwin openly acknowledged that far-reaching conclusion, and expressly
declared his entire agreement with those naturalists who had, in the
meantime, 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 deduction, 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 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
substance_ (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 comprehension, 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 combination, assuming a new form or
combination in consequence 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 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 supernatural 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 advantage 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 commences, 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 imaginings 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 investigate 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, however, in the idea of
creation, although used in this sense, the 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, _development_.
The great value which the _History of Development_ possesses for the
scientific understanding of animal and vegetable 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 former.
The subject of this is furnished to us by the science of petrifactions,
or palæontology, 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
palæontological history of the development of organisms, which we may
term _Phylogeny_, stands in the most important and remarkable relation
to the other branch of organic 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 palæontological 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 supernatural 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 questions, the
Theory of Descent gives us perfectly satisfactory answers—and always
answers which refer to purely mechanical causes, and point to purely
physico-chemical forces as the causes of phenomena which we were
formerly accustomed 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 portion 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 caused the earlier naturalists greater
difficulty than the 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 attention, although most
unscientific men know little or nothing about them. Almost every
organism, almost every animal and plant possesses, besides the obviously
useful arrangements 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 possess 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 movement 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, but which 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 auricular 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 perform 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
insignificant 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 nictitating 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 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,
Cæcilia), 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 rudimentary 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 still 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,), 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-legs 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 affixing the legs.
Moreover, in various vertebrate animals, the single bones of both pairs
of legs are found in all the different stages of imperfection, and often
the degenerate bones and those muscles belonging to them 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 less 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 (Labiatæ), 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,”(4) 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 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
conclusion 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 officers, in
uniform, are furnished with an innocent sword, which is never drawn 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 explained, 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 upon the
appearance 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 suppression 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 Labiatæ is explained,
if we admit that all the plants of this family sprung from one common
ancestor, provided with five 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 universe, which we may designate as the _mechanical_,
and which is opposed to the _teleological_ conception. If we compare
all the ideas of the universe prevalent among different nations at
different times, we can divide them all into two sharply contrasted
groups—a _causal_ or _mechanical_, and a _teleological_ or
_vitalistic_. The latter has prevailed 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 purpose. In
the contemplation of every organism the unavoidable 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 nature. 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 assign 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 distinguished representative in Agassiz. His
celebrated work, “An Essay on Classification,”(5) 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, everyone 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
interaction 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
mediæval 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 relations 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 rather find everywhere 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 überall
Wo der Mensch nicht hinkommt mit seiner Qual.”[1]
are beautiful, but, unfortunately, not true. Man in this respect
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.
Whilst, 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 _twofold principle_, or
_dualistic_ theory, which is necessarily implied in the teleological
conception of the universe. The 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 without 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 _materialistic_, in a certain
sense of that “word of many meanings.”
When a physicist traces the phenomena of motion in electricity 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 Physiology, 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 opposition
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 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 doing 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 Rome, on the 17th 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
animated_, 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 propagation 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 constitutes the highest and
most general merit of the Theory of Descent, as reformed by Darwin.
CHAPTER II.
SCIENTIFIC JUSTIFICATION OF THE THEORY OF DESCENT.
HISTORY OF CREATION ACCORDING TO LINNÆUS.
The Theory of Descent, or Doctrine of Filiation, as the
Monistic Explanation 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 _a posteriori_
knowledge, by Inheritance, into _a priori_
knowledge.—Contrast between the Supernatural Hypotheses
of the Creation according to Linnæus, 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.—Linnæus as the
Founder of the Systematic Description of Nature and
Distinction of Species.—Linnæus’ Classification and
Binary Nomenclature.—Meaning of Linnæus’ Idea of
Species.—His History of Creation.—Linnæus’ 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 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
Mathematical 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
intricate 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 variations 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 _rudimentary
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
explained in the simplest manner by Darwin’s reformed Theory of Descent.
For the present I will only mention the phenomena presented to us by the
_geographical distribution 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 palæontological 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 further to all the general laws of
_Comparative Anatomy_, especially to the great law of _division of
labour_ or _separation_ (polymorphism, or differentiation), 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
development_ 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 of the Doctrine of Descent, no
longer as the ingeniously designed 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 Doctrine of
Filiation, or Descent, we are enabled for the first time to reduce all
organic phenomena to a single law, and to discover 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 phenomena, 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 synthetic comprehension, and by the thoughtful
comparison of a number of well-known 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., _Inheritance 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 organisms, also further
by considering the reciprocal interaction which all animals and plants,
living in one and the same 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 (causæ 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 vegetable
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 organic 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 frequently 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 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 renounce 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 wish 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, which properties have not as yet
been observed by the experience of the senses. But Darwin’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 comprehensive 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 Adaptation 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 unavoidable 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 forms_ which had hitherto been unexplained, it is perhaps
necessary that I should here say a few words about the different ideas
connected 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 properties 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 _nowhere_
arrive at a knowledge of first causes. The origin of every simple salt
crystal, which we obtain by evaporating its mother liquor, is no less
mysterious to us, as far as concerns 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 formation of a chemical
combination, we arrive, by discovering and establishing the active
causes—for example, the gravitation 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, _à priori_ knowledge of man may be brought up;
but we can see that the so-called _à priori_ knowledge can by Darwin’s
theory be proved to have been acquired _à 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 _à priori_. In our late animal ancestors, all our so-called
“_à priori_ knowledge” was originally acquired _à posteriori_, and only
gradually became _à priori_ by inheritance. It is based in the first
instance upon experiences, and by the laws of Inheritance and Adaptation
we can positively prove that knowledge _à priori_ and knowledge _à
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 our knowledge is limited, and we
can never apprehend the _first causes_ of any phenomena. The force of
crystallization, 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 mystery to us and not cognizable in itself.
Before commencing our principal task, which is the careful discussion of
the Doctrine of Descent, and the consequences that arise out of it, let
us take an historical retrospect of the most important and most widely
spread of those views, which before Darwin men had elaborated
concerning organic creation, and the coming into existence of the many
animal and vegetable species. In doing this I have no intention 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 arbitrary fiction, and of a want of a close
observance of nature, to be of interest in a scientific treatment of the
history of creation. 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 immediately take up the scientific
hypothesis about creation, which originated with Linnæus as late as the
commencement of last century.
All the different conceptions which man has ever formed about the coming
into existence of the different animal and vegetable species may
conveniently be divided into two great contrasted groups—the natural
and supernatural histories of creation.
These two groups, on the whole, correspond with the two different
principal forms of the human notions of the universe which we have
already contrasted as the _monistic 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 every individual species of animal and plant an
“embodied creative thought,” the material expression of a _definite
first cause_ (causa finalis) acting for a set purpose. They must
necessarily assume supernatural (not mechanical) processes for the
origin of organisms. With justice, we may therefore designate their
scheme of the world’s growth as the _Supernatural History of Creation_.
Among all such teleological histories of creation, that of Moses has
gained the greatest influence, since even so distinguished a naturalist
as Linnæus 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-miraculous_ 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
mechanical (causal) conception of the universe. In opposition to the
dualistic or teleological conception of nature, our theory considers
organic, as well as inorganic, bodies to be the necessary products of
natural forces. It does not see in every individual 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
expression of a necessarily active cause, that is, of a mechanical cause
(causa efficiens). Where teleological Dualism seeks the arbitrary
thoughts of a capricious Creator in the miracles of creation, causal
Monism finds in the process of development the necessary effects of
eternal immutable laws of nature.
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
whatever to do with each other, namely, scientific and moral
materialism. Scientific materialism, which is identical with our Monism,
affirms 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 knowledge 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
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 maintain 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 philosophers, whose highest happiness
is the intellectual enjoyment of Nature, and whose highest aim is the
knowledge of her laws. We find it in the palaces of ecclesiastical
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 fellow-men. Blind to the infinite grandeur of the
so-called “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, that
_without it there can be no natural science at all_. This principle is
quite inseparable from our Non-miraculous History of Creation, 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 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 great 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
_perfecting_. 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 differentiation of the
originally simple matter. We can therefore bestow our just and sincere
admiration on the Jewish lawgiver’s grand insight into nature, 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 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 Linnæus, 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 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, Linnæus, the founder of modern natural
history, linked his System of Nature most closely to the Mosaic history
of creation.
The extraordinary progress which Charles Linnæus made in the so-called
descriptive natural sciences, consists, as is well known, in his having
established a system of nomenclature 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 Linnæus’ 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 Linnæus’ time, many vain attempts had been made to throw light
upon the endless chaos of different animal and vegetable forms (then
known) by adopting for them suitable names and groupings; but Linnæus,
by a happy hit, succeeded in accomplishing this important and difficult
task, when he established the so-called “_binary nomenclature_.” The
binary nomenclature, or the twofold designation, as Linnæus 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. 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 Linnæus’ plan, the more general and comprehensive generic
name is written first; the special subordinate 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 vegetable kingdom,
according to Linnæus’ 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 Linnæus 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 first time, it became possible to arrange the
immense mass of different organic forms according to their greater or
less degree of resemblance, and to obtain an easy survey of the general
outlines of such a “system.” Linnæus facilitated the 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
comprehensive main divisions or classes. Thus, according to Linnæus,
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 Linnæus’ binary nomenclature in a _practical_ 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 different conceptions of which
Darwinists and Anti-Darwinists fight.
According to Darwin’s opinion, and that of his adherents, the different
species of one and the same genus of animals and plants are nothing else
than differently developed descendants of one and the same original
primary form. The different kinds of pine mentioned above would
accordingly have originated from a single primæval form of pine. In like
manner the origin of all 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 orders 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 independent 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.”
Linnæus 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
diversæ, 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.” Linnæus, 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 earthworm, the garden and
vineyard snails, as well as the great majority of plants, a single
individual.
Linnæus 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 midway 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 Linnæan 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 Linnæus’ clearness and sagacity in other matters, we may
doubt whether he believed it himself. As to the simultaneous origin of
all individuals of each species from one pair of ancestors respectively
(or in the case of the hermaphrodite 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 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 simultaneously been created.
Moreover, how little importance Linnæus himself attached to this
untenable hypothesis of creation is clear, among other things, from the
fact that he recognized _Hybridism_ (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 Linnæus 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 Linnæus gained by his
systematic classification and by his other 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
throughout systematic Zoology and Botany the distinctions,
classification, and designations of species, introduced by Linnæus, 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 prevailing Biblical belief, that his
hypothesis of creation has retained its position so long.
CHAPTER III.
THE HISTORY OF CREATION ACCORDING TO CUVIER 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 Four
Principal Forms (types or branches) of the Animal
Kingdom, by Cuvier and Bär.—Cuvier’s Services to
Palæontology.—His Hypothesis of the Revolutions of our
Globe, and the Epochs of Creation separated by
them.—Unknown Supernatural Causes of the Revolutions,
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.—Rude Conception of the Creator as a man-like
being in Agassiz’s Hypothesis of Creation.—Its internal
Inconsistency and Contradictions with the important
Palæontological 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 entertained about the _nature of species_.
Naturalists either agree with Linnæus, 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 Linnæus’
view (which was discussed in our last chapter), that the different
organic species came into existence independently—that they have no
blood-relationship—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 individual, 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 turn aside from the safe domain of a rational
knowledge of nature, and take refuge in the mythological belief in
miracles.
If, on the other hand, with Darwin, we refer the similarity of form of
the different species to real blood-relationship, 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 genealogical 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_[2]
(archigony, or generatio spontanea). From Darwin’s view of the nature of
species, we arrive therefore at a _natural theory of development_; but
from Linnæus’ conception of the idea of species, we must assume a
_supernatural dogma of creation_.
Most naturalists after Linnæus, whose great services in
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 Linnæus, an
independent creation of individual species, in conformity with the
Mosaic account of creation. The foundation of their conception was based
upon Linnæus’ 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 distinction 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
Müller, makes the following striking observation: “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 followed by others,—so zoology also has its dogmas, which are just
as generally professed as they are denied in practice.” (Für Darwin, p.
71.)(16)
Linnæus’ 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 all organic
individuals which 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 formation 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 Linnæus has exercised the greatest influence on the study of
zoology. In his conception and definition of the idea of species, he
agreed on the whole with Linnæus, 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 foolish
assertion—“The immutability of species is a necessary condition of the
existence of scientific natural history.” As Linnæus’ definition of
species did not satisfy him, he made an attempt to give a more exact
and, for systematic 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 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 common 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 applicable. 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 consequence 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 combat, 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 Linnæus established the
distinction of species, genera, orders, and classes mostly upon external
characters, and upon separate 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 organization. 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 distinguished natural families in the classes
of animals, and established his natural system of the animal kingdom on
their comparative anatomy.
The progress from Linnæus’ artificial system to Cuvier’s natural system
was exceedingly important. Linnæus 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 (Vertebrata); 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 structure or type was
discernible, distinguishing each branch from the three others. In the
Vertebrate animals it is distinctly 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. The Radiate animals, finally, differ
from the three other principal forms by their body being the combination
of four 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. However, the same thought was expressed
almost simultaneously, and independently of Cuvier, by Bär, one of the
greatest naturalists, and still living, who did the most eminent service
in the study of animal development. Bär showed that in the development
of animals, also, four different main forms (or types) must be
distinguished.(20) These correspond with the four plans of structure in
animals, which Cuvier distinguished on the ground of comparative
anatomy. Thus, for example, the individual development of all Vertebrate
animals agrees, from the commencement, so much in its fundamental
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 Bär, who arrived at the distinction of the four animal types or
principal forms through the history of the individual development
(Embryology), nor Cuvier, who arrived at the same conclusion by means
of comparative anatomy, recognized the true cause of this difference.
This is disclosed to us by the Theory of Descent. The wonderful and
astonishing similarity in the inner organization and in the anatomical
relations of structure, and the still more remarkable agreement in the
embryonic development 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 structure 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
Palæontology, that Cuvier rendered great service. We must draw special
attention to this, because these very palæontological 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 promoted at the
beginning of our century in a most extensive manner, and established
quite anew for the Vertebrate 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 creation,” the
infallible and indisputable records which fix the correct history of
organisms upon an irrefragable foundation. 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
collateral lines, which, together with the present living organisms,
branched off 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 impressions 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 knowledge,
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 naturæ), or products of an
unknown formative power or instinct of nature (nisus formativus, vis
plastica). Respecting 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 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
petrifactions were nothing more than such unsuccessful attempts.
According to others, petrifactions originated from the influence 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 16th 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 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 palæontology, however,
belongs to the beginning of our century, when Cuvier published his
classic researches on petrified Vertebrate 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
palæontological laws, which are of great consequence to the history of
creation. Foremost among them stands the assertion that the extinct
species of animals, whose remains we find petrified in the different
strata of the earth’s crust, lying one above another, differ 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 perpendicular section of the stratified
crust of the earth we find that the different 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 was in one
sense, yet in another it became to him the source of a very serious
error. For as he considered the characteristic 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 first 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 from 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 preceding 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 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 débris
at their foot; secondly, _flowing waters_, which carry away this débris
and deposit it as mud in stagnant waters; thirdly, the sea, whose
breakers gnaw at the steep _sea_ coasts, and throw up “dunes” on the
flat sea margins; finally and fourthly, _volcanos_, 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 became the greatest obstacle to the development of a natural
history of the creation. For if such all-destructive revolutions 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 should be obliged to have recourse to the
action of supernatural forces; that is, to the 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
understand an interference of supernatural forces in the natural course
of development of matter.
Just as the great authority which Linnæus 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 systematic distinction implied by it, so the
great services which Cuvier had rendered to the knowledge and
distinction of extinct species became the cause of a general adoption of
his theory of revolutions and catastrophes, and of the false views of
creation connected therewith. The consequence 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 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 catastrophes 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 distinctness of a
series of organic creations maintained its influence, in many ways, in
the science of Palæontology. (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 Classification.”(5)
In this essay Agassiz not only discusses the natural series 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 palæontological, 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 Classification, 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 demonstrates
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 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 teleological 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 our 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 Linnæus, as a form
unchangeable in all its essential characteristics. The species may
indeed change and vary within 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 palæontological
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 which 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 investigating 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 different 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
upon the individual classes, and by various modifications in the
structure of each class, he produced 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 individual 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
imprinted 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 different styles, in various degrees of simplicity, splendour,
greatness, and perfection. This architect would perhaps at first choose
four different 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 different 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 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 scientific 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 succeeds 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 different creations, at last (but very late) he is struck with the
happy thought of creating 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 because, in his earlier scientific works, he had in many
respects actually paved the way for Darwin, especially by his researches
in Palæontology. Among the numerous investigations which created general
interest in the then young science of Palæontology, those of Agassiz,
especially his celebrated work on “Fossil Fish,” rank next in importance
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 importance 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 attention to the remarkable parallelism between the
embryonal and the palæontological development—between ontogeny and
phylogeny, which I have already (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 mammals
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 palæontological development of the whole Vertebrate group was
not only parallel with the embryonic, but also with the systematic
development, that is, with the graduated 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 agreement of the embryonic
and palæontological development, is explained quite simply and naturally
by the Doctrine of Descent, and without it is perfectly inexplicable.
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 Darwin’s Doctrine of Descent, which demonstrates its active
causes. If this doctrine is correct, the perfecting and diversification
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
Inheritance 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 maintained 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 alterations, 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 of 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 degraded to the level of an
idealized man, of an organism progressing in development!
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 scientific 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 himself 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 personal 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 present 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 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 Nature.
CHAPTER IV.
THEORY OF DEVELOPMENT ACCORDING TO GOETHE AND OKEN.
Scientific Insufficiency 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 Natural
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 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 Views of the Common Descent of all
Vertebrate 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 the 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 creatures according to this
plan, as a human architect would his building. If even such eminent
naturalists as Linnæus, Cuvier, and Agassiz, 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 insufficiency 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 found 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 Müller 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 opinion_ about the origin of
species. According to this explanation of the word, we might as well
speak of the creation of cholera, or syphilis, of the creation of a
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 organisms. 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 vegetable species; but all the more if, as we shall see, this theory
explains all facts simply and clearly, as well as completely and
comprehensively. The theories of development 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 fixed 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_ (causæ efficientes), for the
explanation of natural phenomena. In like manner, on the other hand, the
supernatural hypotheses of creation which we have already discussed
coincide completely with the opposite view of the universe, which in
contrast to the former is called the twofold or _dualistic_, often the
_teleological_ or vital, because it traces the organic natural phenomena
to final causes, acting and _working for a definite purpose_ (causæ
finales). It is this deep and intrinsic connection of the different
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) organisms_ out of a single, or out of a very
few, quite simple, and quite imperfect original beings, which came into
existence, 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 intrinsic 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 conceptions 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 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 knowledge 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 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 Linnæus 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 of 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 “Philosophie 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
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
“Natur-philosophie.”
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 experience of the senses, and without any
philosophical activity of thought.
From that time, but especially since 1830, most naturalists 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 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 philosophical 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 general knowledge, can
promote science only in a very slight degree, and the chief value of
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 course of biological development since
Linnæus’ time, we can easily see, as Bär has pointed out, a continual
vacillation between these two tendencies, 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 Linnæus’ 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 speculations 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 nature, to which, after all, all
detailed knowledge of experience 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 great
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, 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 repugnant to Goethe. In
rejecting it he allowed himself not only to be very unjust towards the
most eminent physicists, but to be led into errors which have greatly
injured 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 among Goethe’s writings relating to organic nature
is his _Metamorphosis of Plants_, which appeared 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 fundamental organ he found in
the _leaf_. If at that time the microscope had been generally employed,
if Goethe had examined the structure of organisms by the means of the
microscope he would have gone still further, 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 fundamental 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, 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 metamorphosis 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, vertebræ,—out of which the spine also is composed. The
vertebræ of the skull are like those of the spine, bony rings lying
behind each other, but in the skull are peculiarly 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 explained 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 infinitely 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 _mid
jawbone 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 upper cutting
teeth, are recognized without difficulty in most mammals; in man,
however, they were at that time unknown, and celebrated comparative
anatomists even laid great stress upon this want of a mid jawbone, as
they considered 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 comparing a great 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 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 professional 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 collected
empirical knowledge of those days, the inductive conclusion was arrived
at that all mammals had mid jawbones. 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 may serve to show the great value which we must
ascribe to Goethe’s biological researches. 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 much interwoven with a mass of useless
philosophical fancies, that the latter greatly detract from the former.
Nothing is perhaps more characteristic of the extraordinary 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 Geoffroy 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 importance, as well as an excellent
sketch of the two great opponents. This treatise bears the title
“Principes de Philosophic Zoologique par M. Geoffroy 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. Geoffroy, 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.
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
conclusions 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) conception 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 advantage 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 connection 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 great 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 negotiations behind
closed doors.’ ‘A dreadful affair,’ I answered; ‘but what else could be
expected under the circumstances, 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 Geoffroy de Saint
Hilaire, which has broken out in the Academy, and which is of such great
importance 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 importance,’ 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 nature,
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 different books and chapters a selection of the numerous
interesting and important sentences in which Goethe clearly expresses
his view of organic nature and its constant development. I will here
quote a passage from the poem entitled, “The Metamorphosis of Animals”
(1819).
“All members develop themselves according to eternal laws,
And the rarest form mysteriously 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.”[3]
Here, clearly enough, the contrast between two different organic
constructive forms is intimated, which are opposed to one another, and
which by their interaction 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 conditions, together with an uninterruptedly
progressive transformation, 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
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 organism, 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 counterpoise were not added to it: I mean
the tendency to _specification_, 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 following passage:—“The
triumph of physiological metamorphosis 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 formative tendency of Inheritance or specification; and on the
other hand the progressive, centrifugal, and external formative tendency
of Adaptation, or metamorphosis. This profound biological intuition
could not but lead him naturally 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 of 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 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.(3)
This exceedingly important fundamental 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 distinguished. 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, arrive 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. 398.)
At the time when Goethe in this way sketched the fundamental features of
the Theory of Descent, another German philosopher, Gottfried Reinhold
Treviranus, of 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 successively 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 generative 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 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 passage,
“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 transformation of the animal and
vegetable species, he does not understand 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 interaction of Adaptation and
Inheritance, 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 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 dependent 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 conception 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 maintained 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 entertain a very kindly feeling towards him. Although 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 “Philosophie
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
conceptions. 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 combatted, especially by the
so-called “exact experimentalists,” is the idea that the phenomena of
life in all organisms proceed from a common chemical substance, so to
say, from a general simple _vital-substance_, which he designated by the
name _Urschleim_, 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 aggregation, and possesses the
power, by adaptation to different conditions of existence in the outer
world and by interaction with its material, of producing the most
various forms. Now, we need only change the expression “original slime”
(Urschleim) into _Protoplasm_, or _cell-substance_, 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 exception, there exists a certain quantity of
mucilaginous albuminous matter, in a semi-fluid condition; and that this
nitrogen-holding carbon-compound is exclusively the original 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 without. 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 theory_. For 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 bladders arise from original
semi-fluid globules of the primitive slime, by the fact of their
periphery becoming condensed. The simplest organism, as well as every
animal and every plant of higher kind, is nothing else than “an
accumulation (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) constituent 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 reserved 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 gradual 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 likewise asserted by Oken—“Man
has been developed, not created.” Although many arbitrary perversities
and extravagant fancies may be found in Oken’s philosophy of nature,
they must not prevent us paying our just admiration 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 “Natur-philosophie.”
CHAPTER V.
THEORY OF DEVELOPMENT ACCORDING TO KANT AND LAMARCK.
Kant’s Dualistic Biology.—His Conception of the 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
Showing first 200,000 characters. Full text: gutenberg.org/ebooks/40472