tion
which sugar gives me, and by saltness the sensation of salt. The sugar
and salt I can point out to my neighbor and only in that way I
understand what he means if he says that he tastes salt and sweet;
otherwise I should have no means whatever to discriminate whether that
which he calls a sweet taste sensation is not just what I call headache.
Where no such direct relation for a physical thing is known, description
of the mental element would remain impossible. Of course, every
perception of the outer world, all our seeing and hearing, and touching
and tasting, offers us at once such definite connection between the
inner experience and a piece of the physical universe. Our own organism
is also such a piece of physical nature: just as I describe my tasting
or touching, I may describe the perception of my arms and legs or my
inner organs. Thus everything which is material of perception gives us a
handle for a real psychological description. Psychology usually calls
the elements of these perceptions sensations. Whatever is composed of
sensations is thus describable.

On the other hand, no other way of description is open. If there were
mental states which are composed of other elements than sensations, they
would necessarily remain indescribable; we could not grasp them because
they would not have any definite relation to the common physical world.
We might say, for instance, that our mental content is made up of
sensations and feelings, but if such feelings were really entirely
different from sensations, they would have to remain for all time
mysterious and unknown. We could not compare notes. The feeling which I
call joy may feel just like the one which you call despair. The
consistent development of modern psychology and its emancipation from
vagueness and superficial analysis became possible only through the fact
that such recourse to indescribable elements has become unnecessary.
Modern psychology has been able to demonstrate more and more that the
same elements which constitute our perceptions are also the elements of
the other contents of consciousness. In other words modern psychology
has recognized that the volitions and emotions and feelings and
judgments, and the whole stream of inner life, are made up of
sensations. Millions of sensations in all degrees of vividness and
clearness, of intensity and fusion, in endless manifoldness of rhythms
and relations constitute their whole content. It is a discovery quit