Second, mental action is conditioned by brain action, and runs parallel
therewith. But the brain, so far as we understand it, is given us for
practical behavior. Every current that runs into it from skin or eye or
ear runs out again into muscles, glands, or viscera, and helps to adapt
the animal to the environment from which the current came. It therefore
generalizes and simplifies our view to treat the brain life and the
mental life as having one fundamental kind of purpose.

Third, those very functions of the mind that do not refer directly to
this world's environment, the ethical utopias, æsthetic visions,
insights into eternal truth, and fanciful logical combinations, could
never be carried on at all by a human individual, unless the mind that
produced them in him were also able to produce more practically useful
products. The latter are thus the more essential, or at least the more
primordial results.

Fourth, the inessential 'unpractical' activities are themselves far more
connected with our behavior and our adaptation to the environment than
at first sight might appear. No truth, however abstract, is ever
perceived, that will not probably at some time influence our earthly
action. You must remember that, when I talk of action here, I mean
action in the widest sense. I mean speech, I mean writing, I mean yeses
and noes, and tendencies 'from' things and tendencies 'toward' things,
and emotional determinations; and I mean them in the future as well as
in the immediate present. As I talk here, and you listen, it might seem
as if no action followed. You might call it a purely theoretic process,
with no practical result. But it _must_ have a practical result. It
cannot take place at all and leave your conduct unaffected. If not
to-day, then on some far future day, you will answer some question
differently by reason of what you are thinking now. Some of you will be