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