alization of what we
are doing.

And if we turn to the psychologist, whose business it is to be more
exact and scientific, we find that he gives us only a refinement of
this same criterion. It is important to him to distinguish between
what is given in sensation and what is furnished by memory or
imagination, and he tells us that sensation is the result of a message
conducted along a sensory nerve to the brain.

Here we see emphasized the relation to the body which has been
mentioned above. If we ask the psychologist how he knows that the body
he is talking about is a real body, and not merely an imagined one, he
has to fall back upon the test which is common to us all. A real hand
is one which we see with the eyes open, and which we touch with the
other hand. If our experiences of our own body had not the setting
which marks all sensory experiences, we could never say: I _perceive_
that my body is near the desk. When we call our body real, as
contrasted with things imaginary, we recognize that this group of
experiences belongs to the class described; it is given in sensation,
and is not merely thought of.

It will be observed that, in distinguishing between sensations and
things imaginary, we never go beyond the circle of our experiences. We
do not reach out to a something _beyond_ or _behind_ experiences, and
say: When such a reality is present, we may affirm that we have a
sensation, and when it is not, we may call the experience imaginary.
If there were such a reality as this, it would do us little good, for
since it is not supposed to be perceived directly, we should have to
depend upon the sensations to prove the presence of the reality, and
could not turn to the reality and ask it whether we were or were not
experiencing a sensation. The distinction between sensations and what
is imaginary is an _observed_ distinction. It can be _proved_ that
some experiences are sensory and that some are not. This means that,
in drawing the distinction, we remain within the circle of our
experiences.

There has been much unnecessary mystification touching this supposed
reality behind experiences. In the next chapter we shall see in what
senses the word "reality" may properly be used, and in what sense it
may not. There is a danger in using it loosely and vaguely.

16. MAY WE CALL "THINGS" GROUPS OF SENSATIONS?--Now, the external world
seems to the plain man to be directly given in his sense experiences.
He is w