profound connexion with philosophy, it is to workers in our own day that
we must look for those methods of accurate observation, comparison, and
the study of causes without which it could not advance farther. And
modern psychology has advanced far enough to see that we must include in
its purview the 'soul' of a minnow as well as of a man. Descartes had
stopped too short, for to him animal life, as distinct from human,
showed only the movements of automata. But now, just as the biologist
conceives man as part of one infinite order of living things, so the
psychologist believes that the facts of his consciousness, the crown of
life, must find their place somewhere related to the simplest movements
of the amoeba. Hence the whole of animate evolution, and not only that
part of which Dr. Marett spoke, may be thought of as the growth of soul.

But, the objector will inquire, does this imply the enlargement of every
individual or even of the average or the typical personality? And if
not, what becomes of a 'growth of the soul'?

To this we must admit the impossibility of any complete, or even
approximate, answer with our present knowledge. We can only note one or
two points of certainty or of confident belief. The first, that there
have been individual men, an Aristotle or a Shakespeare, in the past,
with whom later ages never have, and perhaps never may, compare. The
second, that there are good grounds for thinking that the average man
has improved in goodness and in knowledge since we first knew him dimly
in the dawn of history. But more important and more certain is the fact
that the collective soul of man has grown, and all the extensions of
knowledge and of power of which our volume speaks bear witness to it.
They are essentially social in origin and outlook, and rest on a
foundation of common thought immeasurably wider than any in the more
distant past.