mains
but little changed, while the margin alters rapidly. Sometimes the focus
alters, and the margin stays. Sometimes focus and margin change places.
Sometimes, again, abrupt alterations of the whole field occur. There can
seldom be a sharp description. All we know is that, for the most part,
each field has a sort of practical unity for its possessor, and that
from this practical point of view we can class a field with other fields
similar to it, by calling it a state of emotion, of perplexity, of
sensation, of abstract thought, of volition, and the like.

Vague and hazy as such an account of our stream of consciousness may be,
it is at least secure from positive error and free from admixture of
conjecture or hypothesis. An influential school of psychology, seeking
to avoid haziness of outline, has tried to make things appear more exact
and scientific by making the analysis more sharp.

The various fields of consciousness, according to this school, result
from a definite number of perfectly definite elementary mental states,
mechanically associated into a mosaic or chemically combined. According
to some thinkers,--Spencer, for example, or Taine,--these resolve
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, alread