characteristically English thinker: he continues a train of ideas
which Hobbes and Malthus had already begun. Moreover in his critical
views as to the conception of species he had English forerunners; in
the middle ages Occam and Duns Scotus, in the eighteenth century
Berkeley and Hume. In his moral philosophy, as we shall see later, he
is an adherent of the school which is represented by Hutcheson, Home
and Adam Smith. Because he is no philosopher in the stricter sense of
the term, it is of great interest to see that his attitude of mind is
that of the great thinkers of his nation.
In considering Darwin's influence on philosophy we will begin with an
examination of the attitude of philosophy to the conception of
evolution at the time when _The Origin of Species_ appeared. We will
then examine the effects which the theory of evolution, and especially
the idea of the struggle for life, has had, and naturally must have,
on the discussion of philosophical problems.
II
When _The Origin of Species_ appeared fifty years ago Romantic
speculation, Schelling's and Hegel's philosophy, still reigned on the
continent, while in England Positivism, the philosophy of Comte and
Stuart Mill, represented the most important trend of thought. German
speculation had much to say on evolution, it even pretended to be a
philosophy of evolution. But then the word "evolution" was to be taken
in an ideal, not in a real, sense. To speculative thought the forms
and types of nature formed a system of ideas, within which any form
could lead us by continuous transitions to any other. It was a
classificatory system which was regarded as a divine world of thought
or images, within which metamorphoses could go on--a condition
comparable with that in the mind of the poet when one image follows
another with imperceptible changes. Goethe's ideas of evolution, as
expressed in his _Metamorphosen der Pflanzen und der Thiere_, belong
to this category; it is, therefore, incorrect to call him a forerunner
of Darwin. Schelling and Hegel held the same idea; Hegel expressly
rejected the conception of a real evolution in time as coarse and
materialistic. "Nature," he says, "is to be considered as a _system of
stages_, the one necessarily arising from the other, and being the
nearest truth of that from which it proceeds; but not in such a way
that the one is _naturally_ generated by the other; on the contrary
[their connection lies] in the inner idea which is the ground of
nature. The _metamorphosis_ can be ascribed only to the notion as
such, because it alone is evolution.... It has been a clumsy idea in
the older as well as in the newer philosophy of nature, to regard the
transformation and the transition from one natural form and sphere to
a higher as an outward and actual production."[196]
The only one of the philosophers of Romanticism who believed in a
real, historical evolution, a real production of new species, was
Oken.[197] Danish philosophers, such as Treschow (1812) and Sibbern
(1846), have also broached the idea of an historical evolution of all
living beings from the lowest to the highest. Schopenhauer's
philosophy has a more realistic character than that of Schelling's and
Hegel's, his diametrical opposites, although he also belongs to the
romantic school of thought. His philosophical and psychological views
were greatly influenced by French naturalists and philosophers,
especially by Cabanis and Lamarck. He praises the "ever memorable
Lamarck," because he laid so much stress on the "will to live." But he
repudiates as a "wonderful error" the idea that the organs of animals
should have reached their present perfection through a development in
time, during the course of innumerable generations. It was, he said, a
consequence of the low standard of contemporary French philosophy,
that Lamarck came to the idea of the construction of living beings in
time through succession![198]
The positivistic stream of thought was not more in favour of a real
evolution than was the Romantic school. Its aim was to adhere to
positive facts: it looked with suspicion on far-reaching speculation.
Comte laid great stress on the discontinuity found between the
different kingdoms of nature, as well as within each single kingdom.
As he regarded as unscientific every attempt to reduce the number of
physical forces, so he rejected entirely the hypothesis of Lamarck
concerning the evolution of species; the idea of species would in his
eyes absolutely lose its importance if a transition from species to
species under the influence of conditions of life were admitted. His
disciples (Littre, Robin) continued to direct against Darwin the
polemics which their master had employed against Lamarck. Stuart Mill,
who, in the theory of knowledge, represented the empirical or
positivistic movement in philosophy--like his English forerunners from
Locke to Hume--founded his theory of knowledge and morals on the
experience of the single individual. He sympathised with the theory of
the original likeness of all individuals and derived their
differences, on which he practically and theoretically laid much
stress, from the influence both of experience and education, and,
generally, of physical and social causes. He admitted an individual
evolution, and, in the human species, an evolution based on social
progress; but no physiological evolution of species. He was afraid
that the hypothesis of heredity would carry us back to the old theory
of "innate" ideas.
Darwin was more empirical than Comte and Mill; experience disclosed to
him a deeper continuity than they could find; closer than before the
nature and fate of the single individual were shown to be interwoven
in the great web binding the life of the species with nature as a
whole. And the continuity which so many idealistic philosophers could
find only in the world of thought, he showed to be present in the
world of reality.
III
Darwin's energetic renewal of the old idea of evolution has its chief
importance in strengthening the conviction of this real continuity in
the world, of continuity in the series of form and events. It was a
great support for all those who were prepared to base their conception
of life on scientific grounds. Together with the recently discovered
law of the conservation of energy, it helped to produce the great
realistic movement which characterises the last third of the
nineteenth century. After the decline of the Romantic movement people
wished to have firmer ground under their feet and reality now asserted
itself in a more emphatic manner than in the period of Romanticism. It
was easy for Hegel to proclaim that "the real" was "the rational," and
that "the rational" was "the real": reality itself existed for him
only in the interpretation of ideal reason, and if there was anything
which could not be merged in the higher unity of thought, then it was
only an example of the "impotence of nature to hold to the idea." But
now concepts are to be founded on nature and not on any system of
categories too confidently deduced _a priori_. The new devotion to
nature had its recompense in itself, because the new points of view
made us see that nature could indeed "hold to ideas," though perhaps
not to those which we had cogitated beforehand.
A most important question for philosophers to answer was whether the
new views were compatible with an idealistic conception of life and
existence. Some proclaimed that we have now no need of any philosophy
beyond the principles of the conservation of matter and energy and the
principle of natural evolution: existence should and could be
definitely and completely explained by the laws of material nature.
But abler thinkers saw that the thing was not so simple. They were
prepared to give the new views their just place and to examine what
alterations the old views must undergo in order to be brought into
harmony with the new data.
The realistic character of Darwin's theory was shown not only in the
idea of natural continuity, but also, and not least, in the idea of
the cause whereby organic life advances step by step. This idea--the
idea of the struggle for life--implied that nothing could persist, if
it had no power to maintain itself under the given conditions. Inner
value alone does not decide. Idealism was here put to its hardest
trial. In continuous evolution it could perhaps still find an analogy
to the inner evolution of ideas in the mind; but in the demand for
power in order to struggle with outward conditions Realism seemed to
announce itself in its most brutal form. Every form of Idealism had to
ask itself seriously how it was going to "struggle for life" with this
new Realism.
We will now give a short account of the position which leading
thinkers in different countries have taken up in regard to this
question.
I. Herbert Spencer was the philosopher whose mind was best prepared by his
own previous thinking to admit the theory of Darwin to a place in his
conception of the world. His criticism of the arguments which had been put
forward against the hypothesis of Lamarck, showed that Spencer, as a young
man, was an adherent to the evolution idea. In his _Social Statics_ (1850)
he applied this idea to human life and moral civilisation. In 1852 he wrote
an essay on _The Development Hypothesis_, in which he definitely stated his
belief that the differentiation of species, like the differentiation within
a single organism, was the result of development. In the first edition of
his _Psychology_ (1855) he took a step which put him in opposition to the
older English school (from Locke to Mill): he acknowledged "innate ideas"
so far as to admit the tendency of acquired habits to be inherited in the
course of generations, so that the nature and functions of the individual
are only to be understood through its connection with the life of the
species. In 1857, in his essay on _Progress_, he propounded the law of
differentiation as a general law of evolution, verified by examples from
all regions of experience, the evolution of species being only one of these
examples. On the effect which the appearance of _The Origin of Species_ had
on his mind he writes in his _Autobiography_: "Up to that time ... I held
that the sole cause of organic evolution is the inheritance of
functionally-produced modifications. The _Origin of Species_ made it clear
to me that I was wrong, and that the larger part of the facts cannot be due
to any such cause.... To have the theory of organic evolution justified was
of course to get further support for that theory of evolution at large with
which ... all my conceptions were bound up."[199] Instead of the
metaphorical expression "natural selection," Spencer introduced the term
"survival of the fittest," which found favour with Darwin as well as with
Wallace.
In working out his ideas of evolution, Spencer found that
differentiation was not the only form of evolution. In its simplest
form evolution is mainly a concentration, previously scattered
elements being integrated and losing independent movement.
Differentiation is only forthcoming when minor wholes arise within a
greater whole. And the highest form of evolution is reached when there
is a harmony between concentration and differentiation, a harmony
which Spencer calls equilibration and which he defines as a moving
equilibrium. At the same time this definition enables him to
illustrate the expression "survival of the fittest." "Every living
organism exhibits such a moving equilibrium--a balanced set of
functions constituting its life; and the overthrow of this balanced
set of functions or moving equilibrium is what we call death. Some
individuals in a species are so constituted that their moving
equilibria are less easily overthrown than those of other
individuals; and these are the fittest which survive, or, in Mr.
Darwin's language, they are the select which nature preserves."[200]
Not only in the domain of organic life, but in all domains, the summit
of evolution is, according to Spencer, characterised by such a
harmony--by a moving equilibrium.
Spencer's analysis of the concept of evolution, based on a great
variety of examples, has made this concept clearer and more definite
than before. It contains the three elements; integration,
differentiation and equilibration. It is true that a concept which is
to be valid for all domains of experience must have an abstract
character, and between the several domains there is, strictly
speaking, only a relation of analogy. So there is only analogy between
psychical and physical evolution. But this is no serious objection,
because general concepts do not express more than analogies between
the phenomena which they represent. Spencer takes his leading forms
from the material world in defining evolution (in the simplest form)
as integration of matter and dissipation of movement; but as he--not
always quite consistently[201]--assumed a correspondence of mind and
matter, he could very well give these terms an indirect importance for
psychical evolution. Spencer has always, in my opinion with full
right, repudiated the ascription of materialism. He is no more a
materialist than Spinoza. In his _Principles of Psychology_ (Sec. 63) he
expressed himself very clearly: "Though it seems easier to translate
so-called matter into so-called spirit, than to translate so-called
spirit into so-called matter--which latter is indeed wholly
impossible--yet no translation can carry us beyond our symbols." These
words lead us naturally to a group of thinkers whose starting-point
was psychical evolution. But we have still one aspect of Spencer's
philosophy to mention.
Spencer founded his "laws of evolution" on an inductive basis, but he
was convinced that they could be deduced from the law of the
conservation of energy. Such a deduction is, perhaps, possible for the
more elementary forms of evolution, integration and differentiation;
but it is not possible for the highest form, the equilibration, which
is a harmony of integration and differentiation. Spencer can no more
deduce the necessity for the eventual appearance of "moving
equilibria" of harmonious totalities than Hegel could guarantee the
"higher unities" in which all contradictions should be reconciled. In
Spencer's hands the theory of evolution acquired a more decidedly
optimistic character than in Darwin's; but I shall deal later with the
relation of Darwin's hypothesis to the opposition of optimism and
pessimism.
II. While the starting-point of Spencer was biological or
cosmological, psychical evolution being conceived as in analogy with
physical, a group of eminent thinkers--in Germany Wundt, in France
Fouillee, in Italy Ardigo--took, each in his own manner, their
starting-point in psychical evolution as an original fact and as a
type of all evolution, the hypothesis of Darwin coming in as a
corroboration and as a special example. They maintain the continuity
of evolution; they find this character most prominent in psychical
evolution, and this is for them a motive to demand a corresponding
continuity in the material, especially in the organic domain.
To Wundt and Fouillee the concept of will is prominent. They see the
type of all evolution in the transformation of the life of will from
blind impulse to conscious choice; the theories of Lamarck and Darwin
are used to support the view that there is in nature a tendency to
evolution in steady reciprocity with external conditions. The struggle
for life is here only a secondary fact. Its apparent prominence is
explained by the circumstance that the influence of external
conditions is easily made out, while inner conditions can be verified
only through their effects. For Ardigo the evolution of thought was
the starting-point and the type: in the evolution of a scientific
hypothesis we see a progress from the indefinite (_indistinto_) to the
definite (_distinto_), and this is a characteristic of all evolution,
as Ardigo has pointed out in a series of works. The opposition between
_indistinto_ and _distinto_ corresponds to Spencer's opposition
between homogeneity and heterogeneity. The hypothesis of the origin of
differences of species from more simple forms is a special example of
the general law of evolution.
In the views of Wundt and Fouillee we find the fundamental idea of
idealism psychical phenomena as expressions of the innermost nature of
existence. They differ from the older Idealism in the great stress
which they lay on evolution as a real, historical process which is
going on through steady conflict with external conditions. The
Romantic dread of reality is broken. It is beyond doubt that Darwin's
emphasis on the struggle for life as a necessary condition of
evolution has been a very important factor in carrying philosophy back
to reality from the heaven of pure ideas. The philosophy of Ardigo, on
the other side, appears more as a continuation and deepening of
positivism, though the Italian thinker arrived at his point of view
independently of French-English positivism. The idea of continuous
evolution is here maintained in opposition to Comte's and Mill's
philosophy of discontinuity. From Wundt and Fouillee Ardigo differs in
conceiving psychical evolution not as an immediate revelation of the
innermost nature of existence, but only as a single, though the most
accessible example, of evolution.
III. To the French philosophers Boutroux and Bergson, evolution proper
is continuous and qualitative, while outer experience and physical
science give us fragments only, sporadic processes and mechanical
combinations. To Bergson, in his recent work _L'Evolution Creatrice_,
evolution consists in an _elan de vie_ which to our fragmentary
observation and analytic reflexion appears as broken into a manifold
of elements and processes. The concept of matter in its scientific
form is the result of this breaking asunder, essential for all
scientific reflexion. In these conceptions the strongest opposition
between inner and outer conditions of evolution is expressed: in the
domain of internal conditions spontaneous development of qualitative
forms--in the domain of external conditions discontinuity and
mechanical combination.
We see, then, that the theory of evolution has influenced philosophy
in a variety of forms. It has made idealistic thinkers revise their
relation to the real world; it has led positivistic thinkers to find a
closer connection between the facts on which they based their views;
it has made us all open our eyes for new possibilities to arise
through the _prima facie_ inexplicable "spontaneous" variations which
are the condition of all evolution. This last point is one of peculiar
interest. Deeper than speculative philosophy and mechanical science
saw in the days of their triumph, we catch sight of new streams, whose
sources and laws we have still to discover. Most sharply does this
appear in the theory of mutation, which is only a stronger
accentuation of a main point in Darwinism. It is interesting to see
that an analogous problem comes into the foreground in physics through
the discovery of radioactive phenomena, and in psychology through the
assumption of psychical new formations (as held by Boutroux, William
James and Bergson). From this side, Darwin's ideas, as well as the
analogous ideas in other domains, incite us to renewed examination of
our first principles, their rationality and their value. On the other
hand, his theory of the struggle for existence challenges us to
examine the conditions and discuss the outlook as to the persistence
of human life and society and of the values that belong to them. It is
not enough to hope (or fear?) the rising of new forms; we have also to
investigate the possibility of upholding the forms and ideals which
have hitherto been the bases of human life. Darwin has here given his
age the most earnest and most impressive lesson. This side of Darwin's
theory is of peculiar interest to some special philosophical problems
to which I now pass.
IV
Among philosophical problems the problem of knowledge has in the last
century occupied a foremost place. It is natural, then, to ask how
Darwin and the hypothesis whose most eminent representative he is,
stand to this problem.
Darwin started an hypothesis. But every hypothesis is won by inference
from certain presuppositions, and every inference is based on the
general principles of human thought. The evolution hypothesis
presupposes, then, human thought and its principles. And not only the
abstract logical principles are thus pre-supposed. The evolution
hypothesis purports to be not only a formal arrangement of phenomena,
but to express also the law of a real process. It supposes, then, that
the real data--all that in our knowledge which we do not produce
ourselves, but which we in the main simply receive--are subject to
laws which are at least analogous to the logical relations of our
thoughts; in other words, it assumes the validity of the principle of
causality. If organic species could arise without cause there would be
no use in framing hypotheses. Only if we assume the principle of
causality, is there a problem to solve.
Though Darwinism has had a great influence on philosophy considered as
a striving after a scientific view of the world, yet here is a point
of view--the epistemological--where philosophy is not only independent
but reaches beyond any result of natural science. Perhaps it will be
said: the powers and functions of organic beings only persist (perhaps
also only arise) when they correspond sufficiently to the conditions
under which the struggle of life is to go on. Human thought itself is,
then, a variation (or a mutation) which has been able to persist and
to survive. Is not, then, the problem of knowledge solved by the
evolution hypothesis? Spencer had given an affirmative answer to this
question before the appearance of _The Origin of Species_. For the
individual, he said, there is an _a priori_, original, basis (or
_Anlage_) for all mental life; but in the species all powers have
developed in reciprocity with extendal conditions. Knowledge is here
considered from the practical point of view, as a weapon in the
struggle for life, as an "organon" which has been continuously in use
for generations. In recent years the economic or pragmatic
epistemology, as developed by Avenarius and Mach in Germany, and by
James in America, points in the same direction. Science, it is said,
only maintains those principles and presuppositions which are
necessary to the simplest and clearest orientation be applied to
experience and to practical work, will successively be eliminated.
In these views a striking and important application is made of the
idea of struggle for life to the development of human thought. Thought
must, as all other things in the world, struggle for life. But this
whole consideration belongs to psychology, not to the theory of
knowledge (epistemology), which is concerned only with the validity of
knowledge, not with its historical origin. Every hypothesis to explain
the origin of knowledge must submit to cross-examination by the theory
of knowledge, because it works with the fundamental forms and
principles of human thought. We cannot go further back than these
forms and principles, which it is the aim of epistemology to ascertain
and for which no further reason can be given.[202]