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 importa