and the higher mental faculties.[184] His object, he says, is to show
that there is no fundamental difference between man and the higher
mammals in their mental faculties; that these faculties are variable
and the variations tend to be inherited; and that under natural
selection beneficial variations of all kinds will have been preserved
and injurious ones eliminated.
Darwin was too good an observer and too honest a man to minimise the
"enormous difference" between the level of mental attainment of
civilised man and that reached by any animal. His contention was that
the difference, great as it is, is one of degree and not of kind. He
realised that, in the development of the mental faculties of man, new
factors in evolution have supervened--factors which play but a
subordinate and subsidiary part in animal intelligence.
Intercommunication by means of language, approbation and blame, and
all that arises out of reflective thought, are but foreshadowed in the
mental life of animals. Still he contends that these may be explained
on the doctrine of evolution. He urges[185] "that man is variable in
body and mind; and that the variations are induced, either directly or
indirectly, by the same general causes, and obey the same general
laws, as with the lower animals." He correlates mental development
with the evolution of the brain.[186] "As the various mental faculties
gradually developed themselves, the brain would almost certainly
become larger. No one, I presume, doubts that the large proportion
which the size of man's brain bears to his body, compared to the same
proportion in the gorilla or orang, is closely connected with his
higher mental powers." "With respect to the lower animals," he
says,[187] "M. E. Lartet,[188] by comparing the crania of tertiary and
recent mammals belonging to the same groups, has come to the
remarkable conclusion that the brain is generally larger and the
convolutions are more complex in the more recent form."
Sir E. Ray Lankester has sought to express in the simplest terms the
implications of the increase in size of the cerebrum. "In what," he
asks, "does the advantage of a larger cerebral mass consist?" "Man,"
he replies, "is born with fewer ready-made tricks of the
nerve-centres--these performances of an inherited nervous mechanism so
often called by the ill-defined term 'instincts'--than are the monkeys
or any other animal. Correlated with the absence of inherited
ready-made mechanism, man has a greater capacity of developing in the
course of his individual growth similar nervous mechanisms (similar
to but not identical with those of 'instinct') than any other
animal.... The power of being educated--'educability' as we may term
it--is what man possesses in excess as compared with the apes. I think
we are justified in forming the hypothesis that it is this
'educability' which is the correlative of the increased size of the
cerebrum." There has been natural selection of the more educable
animals, for "the character which we describe as 'educability' can be
transmitted, it is a congenital character. But the _results_ of
education can _not_ be transmitted. In each generation they have to be
acquired afresh, and with increased 'educability' they are more
readily acquired and a larger variety of them.... The fact is that
there is no community between the mechanisms of instinct and the
mechanisms of intelligence, and that the latter are later in the
history of the evolution of the brain than the former and can only
develop in proportion as the former become feeble and defective."[189]
In this statement we have a good example of the further development of
views which Darwin foreshadowed but did not thoroughly work out. It
states the biological case clearly and tersely. Plasticity of
behaviour in special accommodation to special circumstances is of
survival value; it depends upon acquired characters; it is correlated
with increase in size and complexity of the cerebrum; under natural
selection therefore the larger and more complex cerebrum as the organ
of plastic behaviour has been the outcome of natural selection. We
have thus the biological foundations for a further development of
genetic psychology.
There are diversities of opinion, as Darwin showed, with regard to the
range of instinct in man and the higher animals as contrasted with
lower types. Darwin himself said[190] that "Man, perhaps, has somewhat
fewer instincts than those possessed by the animals which come next to
him in the series." On the other hand, Prof. Wm. James says[191] that
man is probably the animal with most instincts. The true position is
that man and the higher animals have fewer complete and self-sufficing
instincts than those which stand lower in the scale of mental
evolution, but that they have an equally large or perhaps larger mass
of instinctive raw material which may furnish the stuff to be
elaborated by intelligent processes. There is, perhaps, a greater
abundance of the primary tissue of experience to be refashioned and
integrated by secondary modification; there is probably the same
differentiation in relation to the determining biological ends, but
there is at the outset less differentiation of the particular and
specific modes of behaviour. The specialised instinctive performances
and their concomitant experience-complexes are at the outset more
indefinite. Only through acquired connections, correlated with
experience, do they become definitely organised.
The full working-out of the delicate and subtle relationship of
instinct and educability--that is, of the hereditary and the acquired
factors in the mental life--is the task which lies before genetic and
comparative psychology. They interact throughout the whole of life,
and their interactions are very complex. No one can read the chapters
of _The Descent of Man_ which Darwin devotes to a consideration of the
mental characters of man and animals without noticing, on the one
hand, how sedulous he is in his search for hereditary foundations,
and, on the other hand, how fully he realises the importance of
acquired habits of mind. The fact that educability itself has innate
tendencies--is in fact a partially differentiated educability--renders
the unravelling of the factors of mental progress all the more
difficult.
In his comparison of the mental powers of men and animals it was
essential that Darwin should lay stress on points of similarity rather
than on points of difference. Seeking to establish a doctrine of
evolution, with its basal concept of continuity of process and
community of character, he was bound to render clear and to emphasise
the contention that the difference in mind between man and the higher
animals, great as it is, is one of degree and not of kind. To this end
Darwin not only recorded a large number of valuable observations of
his own, and collected a considerable body of information from
reliable sources, he presented the whole subject in a new light and
showed that a natural history of mind might be written and that this
method of study offered a wide and rich field for investigation. Of
course those who regarded the study of mind only as a branch of
metaphysics smiled at the philosophical ineptitude of the mere man of
science. But the investigation, on natural history lines, has been
prosecuted with a large measure of success. Much indeed still remains
to be done; for special training is required, and the workers are
still few. Promise for the future is however afforded by the fact that
investigation is prosecuted on experimental lines and that something
like organised methods of research are taking form. There is now but
little reliance on casual observations recorded by those who have not
undergone the necessary discipline in these methods. There is also
some change of emphasis in formulating conclusions. Now that the
general evolutionary thesis is fully and freely accepted by those who
carry on such researches, more stress is laid on the differentiation
of the stages of evolutionary advance than on the fact of their
underlying community of nature. The conceptual intelligence which is
especially characteristic of the higher mental procedure of man is
more firmly distinguished from the perceptual intelligence which he
shares with the lower animals--distinguished now as a higher product
of evolution, no longer as differing in origin or different in kind.
Some progress has been made, on the one hand in rendering an account
of intelligent profiting by experience under the guidance of pleasure
and pain in the perceptual field, on lines predetermined by
instinctive differentiation for biological ends, and on the other hand
in elucidating the method of conceptual thought employed, for
example, by the investigator himself in interpreting the perceptual
experience of the lower animals.
Thus there is a growing tendency to realise more fully that there are
two orders of educability--first an educability of the perceptual
intelligence based on the biological foundation of instinct, and
secondly an educability of the conceptual intelligence which
refashions and rearranges the data afforded by previous inheritance
and acquisition. It is in relation to this second and higher order of
educability that the cerebrum of man shows so large an increase of
mass and a yet larger increase of effective surface through its rich
convolutions. It is through educability of this order that the human
child is brought intellectually and affectively into touch with the
ideal constructions by means of which man has endeavoured, with more
or less success, to reach an interpretation of nature, and to guide
the course of the further evolution of his race--ideal constructions
which form part of man's environment.
It formed no part of Darwin's purpose to consider, save in broad
outline, the methods, or to discuss in any fulness of detail the
results of the process by which a differentiation of the mental
faculties of man from those of the lower animals has been brought
about--a differentiation the existence of which he again and again
acknowledges. His purpose was rather to show that, notwithstanding
this differentiation, there is basal community in kind. This must be
remembered in considering his treatment of the biological foundations
on which man's systems of ethics are built. He definitely stated that
he approached the subject "exclusively from the side of natural
history."[192] His general conclusion is that the moral sense is
fundamentally identical with the social instincts, which have been
developed for the good of the community; and he suggests that the
concept which thus enables us to interpret the biological ground-plan
of morals also enables us to frame a rational ideal of the moral end.
"As the social instincts," he says,[193] "both of man and the lower
animals have no doubt been developed by nearly the same steps, it
would be advisable, if found practicable, to use the same definition
in both cases, and to take as the standard of morality, the general
good or welfare of the community, rather than the general happiness."
But the kind of community for the good of which the social instincts
of animals and primitive men were biologically developed may be
different from that which is the product of civilisation, as Darwin no
doubt realised. Darwin's contention was that conscience is a social
instinct and has been evolved because it is useful to the tribe in the
struggle for existence against other tribes. One the other hand J. S.
Mill urged that the moral feelings are not innate but acquired, and
Bain held the same view, believing that the moral sense is acquired by
each individual during his life-time. Darwin, who notes[194] their
opinion with his usual candour, adds that "on the general theory of
evolution this is at least extremely improbable." It is impossible to
enter into the question here: much turns on the exact connotation of
the terms "conscience" and "moral sense," and on the meaning we attach
to the statement that the moral sense is fundamentally identical with
the social instincts.
Presumably the majority of those who approach the subjects discussed
in the third, fourth, and fifth chapters of _The Descent of Man_ in
the full conviction that mental phenomena, not less than organic
phenomena, have a natural genesis, would, without hesitation, admit
that the intellectual and moral systems of civilised man are ideal
constructions, the products of conceptual thought, and that as such
they are, in their developed form, acquired. The moral sentiments are
the emotional analogues of highly developed concepts. This does not
however imply that they are outside the range of natural history
treatment. Even though it may be desirable to differentiate the moral
conduct of men from the social behaviour of animals (to which some
such term as "pre-moral" or "quasi-moral" may be applied), still the
fact remains that, as Darwin showed, there is abundant evidence of the
occurrence of such social behaviour--social behaviour which, even
granted that it is in large part intelligently acquired, and is itself
so far a product of educability, is of survival value. It makes for
that integration without which no social group could hold together and
escape elimination. Furthermore, even if we grant that such behaviour
is intelligently acquired, that is to say arises through the
modification of hereditary instincts and emotions, the fact remains
that only through these instinctive and emotional data is afforded the
primary tissue of the experience which is susceptible of such
modification.
Darwin sought to show, and succeeded in showing, that for the
intellectual and moral life there are instinctive foundations which a
biological treatment alone can disclose. It is true that he did not in
all cases analytically distinguish the foundations from the
superstructure. Even to-day we are scarcely in a position to do so
adequately. But his treatment was of great value in giving an impetus
to further research. This value indeed can scarcely be over-estimated.
And when the natural history of the mental operations shall have been
written, the cardinal fact will stand forth, that the instinctive and
emotional foundations are the outcome of biological evolution and have
been ingrained in the race through natural selection. We shall more
clearly realise that educability itself is a product of natural
selection, though the specific results acquired through cerebral
modifications are not transmitted through heredity. It will, perhaps,
also be realised that the instinctive foundations of social behaviour
are, for us, somewhat out of date and have undergone but little change
throughout the progress of civilisation, because natural selection has
long since ceased to be the dominant factor in human progress. The
history of human progress has been mainly the history of man's higher
educability, the products of which he has projected on to his
environment. This educability remains on the average what it was a
dozen generations ago; but the thought-woven tapestry of his
surroundings is refashioned and improved by each succeeding
generation. Few men have in greater measure enriched the
thought-environment with which it is the aim of education to bring
educable human beings into vital contact, than has Charles Darwin. His
special field of work was the wide province of biology; but he did
much to help us to realise that mental factors have contributed to
organic evolution and that in man, the highest product of Evolution,
they have reached a position of unquestioned supremacy.
FOOTNOTES:
[Footnote 153: _Origin of Species_ (6th edit.), p. 205.]
[Footnote 154: _Descent of man_ (2nd edit. 1888), Vol. I. p. 99;
Popular edit. p. 99.]
[Footnote 155: _Ibid._ p. 99.]
[Footnote 156: _The Expression of the Emotions_ (2nd edit.), p. 32.]
[Footnote 157: _Descent of Man_, Vol. II. p. 435.]
[Footnote 158: _Ibid._ 437, 438.]
[Footnote 159: _Origin of Species_ (6th edit.), p. 205.]
[Footnote 160: _Origin of Species_ (6th edit.), p. 205.]
[Footnote 161: _Ibid._ p. 233.]
[Footnote 162: _Ibid._ p. 205.]
[Footnote 163: _Origin of Species_ (6th edit.), p. 233.]
[Footnote 164: _Origin of Species_, pp. 210, 211.]
[Footnote 165: Independently suggested, on somewhat different lines,
by Profs. J. Mark Baldwin, Henry F. Osborn and the writer.]
[Footnote 166: _Origin of Species_ (6th edit.), p. 206.]
[Footnote 167: _Expression of the Emotions_, p. 13. The passage is
here somewhat condensed.]
[Footnote 168: _Ibid._ p. 368.]
[Footnote 169: _Expression of the Emotions_, pp. 373, 374.]
[Footnote 170: _Ibid._ p. 368.]
[Footnote 171: _Ibid._ p. 369.]
[Footnote 172: _Expression of the Emotions_, pp. 65 ff.]
[Footnote 173: Cf. William James, _Principles of Psychology_, Vol. II.
Chap. XXV, New York, 1890.]
[Footnote 174: _Darwinism_, pp. 282, 283, London, 1889.]
[Footnote 175: _Ibid._ p. 283.]
[Footnote 176: _Darwinism_, pp. 283, 284.]
[Footnote 177: _Descent of Man_ (2nd edit.), Vol. II. pp. 136, 137;
(Popular edit.), pp. 642, 643.]
[Footnote 178: _The Play of Animals_, p. 244, London, 1898.]
[Footnote 179: _Ibid._ p. 283.]
[Footnote 180: _Descent of Man_, Vol. II. p. 60; (Popular edit.), p.
566.]
[Footnote 181: _The Play of Animals_, p. 76.]
[Footnote 182: _Ibid._ p. 75.]
[Footnote 183: _The Play of Animals_ p. 24.]
[Footnote 184: _Descent of Man_ (1st edit.), Chaps. II, III, V; (2nd
edit.), Chaps. III, IV, V.]
[Footnote 185: _Descent of Man_, Vol. I. pp. 70, 71; (Popular edit.),
pp. 70, 71.]
[Footnote 186: _Ibid._ p. 81.]
[Footnote 187: _Ibid._ (Popular edit.), p. 82.]
[Footnote 188: _Comptes Rendus des Sciences_, June 1, 1868.]
[Footnote 189: _Nature_, Vol. LXI. pp. 624, 625 (1900).]
[Footnote 190: _Descent of Man_, Vol. I. p. 100.]
[Footnote 191: _Principles of Psychology_, Vol. II. p. 289.]
[Footnote 192: _Descent of Man_, Vol. I. p. 149.]
[Footnote 193: _Descent of Man_, p. 185.]
[Footnote 194: _Ibid._ p. 150 (footnote).]
VII
THE INFLUENCE OF THE CONCEPTION OF EVOLUTION ON MODERN PHILOSOPHY
BY H. HOeFFDING
_Professor of Philosophy in the University of Copenhagen_
I
It is difficult to draw a sharp line between philosophy and natural
science. The naturalist who introduces a new principle, or
demonstrates a fact which throws a new light on existence, not only
renders an important service to philosophy but is himself a
philosopher in the broader sense of the word. The aim of philosophy in
the stricter sense is to attain points of view from which the
fundamental phenomena and the principles of the special sciences can
be seen in their relative importance and connection. But philosophy in
this stricter sense has always been influenced by philosophy in the
broader sense. Greek philosophy came under the influence of logic and
mathematics, modern philosophy under the influence of natural science.
The name of Charles Darwin stands with those of Galileo, Newton, and
Robert Mayer--names which denote new problems and great alterations in
our conception of the universe.
First of all we must lay stress on Darwin's own personality. His deep love
of truth, his indefatigable inquiry, his wide horizon, and his steady
self-criticism make him a scientific model, even if his results and
theories should eventually come to possess mainly an historical interest.
In the intellectual domain the primary object is to reach high summits
from which wide surveys are possible, to reach them toiling honestly
upwards by the way of experience, and then not to turn dizzy when a summit
is gained. Darwinians have sometimes turned dizzy, but Darwin never. He saw
from the first the great importance of his hypothesis, not only because of
its solution of the old problem as to the value of the concept of species,
not only because of the grand picture of natural evolution which it
unrolls, but also because of the life and inspiration its method would
impart to the study of comparative anatomy, of instinct and of heredity,
and finally because of the influence it would exert on the whole conception
of existence. He wrote in his note-book in the year 1837: "My theory would
give zest to recent and fossil comparative anatomy; it would lead to the
study of instinct, heredity, and mind-heredity, whole [of]
metaphysics."[195]
We can distinguish four main points in which Darwin's investigations
possess philosophical importance.
The evolution hypothesis is much older than Darwin; it is, indeed, one
of the oldest guessings of human thought. In the eighteenth century is
was put forward by Diderot and Lamettrie and suggested by Kant (1786).
As we shall see later, it was held also by several philosophers in the
first half of the nineteenth century. In his preface to _The Origin of
Species_, Darwin mentions the naturalists who were his forerunners.
But he has set forth the hypothesis of evolution in so energetic and
thorough a manner that it perforce attracts the attention of all
thoughtful men in a much higher degree than it did before the
publication of the _Origin_.
And further, the importance of his teaching rests on the fact that he,
much more than his predecessors, even than Lamarck, sought a
foundation for his hypothesis in definite facts. Modern science began
by demanding--with Kepler and Newton--evidence of _varae causae_; this
demand Darwin industriously set himself to satisfy--hence the wealth
of material which he collected by his observations and his
experiments. He not only revived an old hypothesis, but he saw the
necessity of verifying it by facts. Whether the special cause on which
he founded the explanation of the origin of species--Natural
Selection--is sufficient, is now a subject of discussion. He himself
had some doubt in regard to this question, and the criticisms which
are directed against his hypothesis hit Darwinism rather than Darwin.
In his indefatigable search for empirical evidence he is a model even
for his antagonists: he has compelled them to approach the problems of
life along other lines than those which were formerly followed.
Whether the special cause to which Darwin appealed is sufficient or not, at
least to it is probably due the greater part of the influence which he has
exerted on the general trend of thought. "Struggle for existence" and
"natural selection" are principles which have been applied, more or less,
in every department of thought. Recent research, it is true, has discovered
greater empirical discontinuity--leaps, "mutations"--whereas Darwin
believed in the importance of small variations slowly accumulated. It has
also been shown by the experimental method, which in recent biological work
has succeeded Darwin's more historical method, that types once constituted
possess great permanence, the fluctuations being restricted within clearly
defined boundaries. The problem has become more precise, both as to
variation and as to heredity. The inner conditions of life have in both
respects shown a greater independence than Darwin had supposed in his
theory, though he always admitted that the cause of variation was to him a
great enigma, "a most perplexing problem," and that the struggle for life
could only occur where variation existed. But, at any rate, it was of the
greatest importance that Darwin gave a living impression of the struggle
for life which is everywhere going on, and to which even the highest forms
of existence must be amenable. The philosophical importance of these ideas
does not stand or fall with the answer to the question, whether natural
selection is a sufficient explanation of the origin of species or not it
has an independent, positive value for everyone who will observe life and
reality with an unbiased mind.