Then, too, considered merely as part of the outside world of matter,
man's body is the physical fact with which he is most in contact and
most immediately concerned. It furnishes him with information concerning
the existence and operations of other minds. It is in fact his only
source of information about the outside world.

First of all, then, you must form definite and intelligent conclusions
concerning the relations between the mind and the body.

[Sidenote: Manner of Handling Mental Processes]

This will be of value in a number of ways. In the first place, you will
understand the bodily mechanism through which the mind operates, and a
knowledge of this mechanism is bound to enlighten you as to the
character of the _mental_ processes themselves. In the second place, it
is worth while to know the extent of the mind's influence over the body,
because this knowledge is the first step toward obtaining bodily
efficiency through the mental control of bodily functions. And, finally,
a study of this bodily mechanism is of very great practical importance
in itself, for the body is the instrument through which the mind acts in
its relations with the world at large.

From a study of the bodily machine, we shall advance to a consideration
of the mental processes themselves, not after the usual manner of works
on psychology, but solely from the standpoint of practical utility and
for the establishment of a scientific concept of the mind capable of
everyday use.

[Sidenote: Fundamental Laws and Practical Methods]