s 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