e in harmony with the ether-waves set in
action by the sun are nerve-ends that are connected with the brain
center devoted to sight. "If," says Professor James, "we could
splice the outer extremities of our optic nerves to our ears,
and those of our auditory nerves to our eyes, we should hear the
lightning and see the thunder, see the symphony and hear the
conductor's movements."

[Sidenote: _Importance of the Mental Make-Up_]

In other words, the kind of impressions we receive from the world
about us, the sort of mental pictures we form concerning it, in fact
the character of the outer world, the nature of the environment in
which our lives are cast--_all these things depend for each one of
us simply upon how he happens to be put together, simply upon his
individual mental make-up_.

There is another way of examining into the intervening agencies that
influence our mental conception of the material world about us.

[Sidenote: _Unreality of "The Real"_]

Look at the table or any other familiar object in the room in which
you are sitting. Has it ever occurred to you that this object may
have no existence apart from your mental impression of it? Have you
ever realized that no object ever has been or ever could be known
to exist unless there was an individual mind present to note its
existence?

If you have never given much thought to questions of this kind,
you will be tempted to answer boldly that the table is obviously a
reality, that you have a direct intuitive knowledge of it, and that
you can at once assure yourself of its existence by looking at it
or touching it. You will conceive your perception of the table as
a sort of projection of your mind comfortably enfolding the table
within itself.

[Sidenote: _"Things" and their Mental Duplicates_]

But perception is obviously only a state of mind. Can it, then, go
outside of the mind to meet the table or even "hover in midair like
a bridge between the two"? If you perceive the table, must not your
perception of it exist wholly within your own mind? If, then, the
table has any existence outside of and apart from your perception
of it, then the table and your mental image of the table are two
separate and distinct things.

In other words, you are on the horns of a dilemma. If you insist
that the table exists _outside_ of your mind, you must admit that
your knowledge of it is not direct, immediate and intuitive, but
_indirect_ and representative, because of in