themselves at last into little elementary psychic particles or atoms of
'mind-stuff,' out of which all the more immediately known mental states
are said to be built up. Locke introduced this theory in a somewhat
vague form. Simple 'ideas' of sensation and reflection, as he called
them, were for him the bricks of which our mental architecture is built
up. If I ever have to refer to this theory again, I shall refer to it as
the theory of 'ideas.' But I shall try to steer clear of it altogether.
Whether it be true or false, it is at any rate only conjectural; and,
for your practical purposes as teachers, the more unpretending
conception of the stream of consciousness, with its total waves or
fields incessantly changing, will amply suffice.[A]

[A] In the light of some of the expectations that are abroad
concerning the 'new psychology,' it is instructive to read
the unusually candid confession of its founder Wundt, after
his thirty years of laboratory-experience:

"The service which it [the experimental method] can yield
consists essentially in perfecting our inner observation, or
rather, as I believe, in making this really possible, in any
exact sense. Well, has our experimental self-observation, so
understood, already accomplished aught of importance? No
general answer to this question can be given, because in the
unfinished state of our science, there is, even inside of the
experimental lines of inquiry, no universally accepted body
of psychologic doctrine....

"In such a discord of opinions (comprehensible enough at a
time of uncertain and groping development), the individual
inquirer can only tell for what views and insights he himself