f the struggle for existence.
Marx himself, in "Das Kapital", indicated another analogy when he dwelt
upon the importance of a general technology for the explanation of this
psychology:--a history of tools which would be to social organs what
Darwinism is to the organs of animal species. And the very importance
they attach to tools, to apparatus, to machines, abundantly proves that
neither Marx nor Engels were likely to forget the special characters
which mark off the human world from the animal. The former always
remains to a great extent an artificial world. Inventions change the
face of its institutions. New modes of production revolutionise not only
modes of government, but modes even of collective thought. Therefore it
is that the evolution of society is controlled by laws special to it, of
which the spectacle of nature offers no suggestion.

If, however, even in this special sphere, it can still be urged that
the evolution of the material conditions of society is in accord
with Darwin's theory, it is because the influence of the methods of
production is itself to be explained by the incessant strife of the
various classes with each other. So that in the end Marx, like Darwin,
finds the source of all progress in struggle. Both are grandsons of
Heraclitus:--polemos pater panton. It sometimes happens, in these days,
that the doctrine of revolutionary socialism is contrasted as rude and
healthy with what may seem to be the enervating tendency of "solidarist"
philanthropy: the apologists of the doctrine then pride themselves above
all upon their faithfulness to Darwinian principles.

So far we have been mainly concerned to show the use that social
philosophies have made of the Darwinian laws for practical purposes:
in order to orientate society towards their ideals each school tries to
show that the authority of natural science is on its side. But even
in the most objective of theories, those which systematically make
abstraction of all political tendencies in order to study the social
reality in itself, traces of Darwinism are readily to be found.

Let us take for example Durkheim's theory of Division of Labour ("De la
Division du Travail social", Paris, 1893.) The conclusions he
derives from it are that whenever professional specialisation causes
multiplication of distinct branches of activity, we get organic
solidarity--implying differences--substituted for mechanical solidarity,
based upon likenesses. The umbilic