am therefore compelled to adopt the compound word pleasure-
pain for my purpose, this having the convenience of being
clear in its intention, even if a little cumbersome in form.

Pleasure and Pain being original mental states are, strictly
speaking, undefinable; but, as is the case with all such
original states, they, may be explained and described by
making clear their relations to other mental states.

All of us who feel sharp sense pains, and a small number
of us, viz. neurologists and physicians, who are experimenting
with sense organs, or are dealing with mental states involving
sense pains, are wont to speak of all pains as sensations -- a
term which is properly employed to designate mental states
connected with action from without upon our well-recognised
sense organs, the eye, the ear, the nose, the skin, etc. That a
classification of pleasure-pain with sensation will not hold
is apparent upon consideration (p. 15 ff.), and indeed is not
generally thought to hold with relation to pleasures, which
are more often classed with emotions.

If we attempt to classify pleasure and pain with the emotions
(p. 32 ff.), however, we are compelled to claim that pleasures
and pains are themselves emotions, and thus defend a more
complete separation of pleasure-pain from sensation than will
be acknowledged; or else we must practically identify emotions
and pleasure-pain, adopting the theory that emotions are
mere complexes of pleasures and pains, as has not infrequently
been done. This latter hypothesis, however, is one which I
think is without warrant. The impossibility of this classi-
fication of pleasure-pain with emotion, which becomes apparent
when we consider their marked difference of quality, is
emphasised especially when we take note of the very diverse
manner of their rise into consciousness. There is no typical.
emotion which fades into another, as pleasure does into pain,
without other marked changes in the mental states involved;
nor is there any which is aroused both by such simple states

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