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.”