irectly only his own mind, and not
another's. You and I may look into each other's face and there guess the
meaning that lies back of the smile or frown or flash of the eye, and
so read something of the mind's activity. But neither directly meets the
other's mind. I may learn to recognize your features, know your voice,
respond to the clasp of your hand; but the mind, the consciousness,
which does your thinking and feels your joys and sorrows, I can never
know completely. Indeed I can never know your mind at all except through
your bodily acts and expressions. Nor is there any way in which you can
reveal your mind, your spiritual self, to me except through these means.

It follows therefore that only _you_ can ever know _you_ and only _I_
can ever know _I_ in any first-hand and immediate way. Between your
consciousness and mine there exists a wide gap that cannot be bridged.
Each of us lives apart. We are like ships that pass and hail each other
in passing but do not touch. We may work together, live together, come
to love or hate each other, and yet our inmost selves forever stand
alone. They must live their own lives, think their own thoughts, and
arrive at their own destiny.

INTROSPECTION THE ONLY MEANS OF DISCOVERING NATURE OF
CONSCIOUSNESS.--What, then, is mind? What is the thing that we call
consciousness? No mere definition can ever make it clearer than it is at
this moment to each of us. The only way to know what mind is, is to look
in upon our own consciousness and observe what is transpiring there. In
the language of the psychologist, we must _introspect_. For one can
never come to understand the nature of mind and its laws of working by
listening to lectures or reading text books alone. There is no
_psychology_ in the text, but only in your living, flowing stream of
thought and mine. True, the lecture and the book may tell us what to
look for when we introspect, and how to understand what we find. But the
statements and descriptions about our minds must be verified by our own
observation and experience before they become vital truth to us.

HOW WE INTROSPECT.--Introspection is something of an art; it has to be
learned. Some master it easily, some with more difficulty, and some, it
is to be feared, never become skilled in its use. In order to introspect
one must catch himself unawares, so to speak, in the very act of
thinking, remembering, deciding, loving, hating, and all the rest. These
fleeting phases of