follow violent activities, from which arise (X) views closely
allied to those discussed under A, pleasure being held to be
due to equilibrium and pain to tension; and again (Y)
certain contrast theories, according to which pleasure is
merely the mark of the absence of pain, or pain the state of
absence of pleasure.

The theories indicated by the letter X fail, as did those of
class A, because they leave the pleasures of exercise un-
accounted for. The theories indicated by Y show their
weakness as soon as we consider that many pleasures arise
out of states which involve no pain whatever (the pleasures,
for instance, which the healthy man appreciates in any
exercise after restful sleep), and that many pains arise out
of states which involve no pleasure.

C (p. 177 ff.). The pains of restriction with which life is
filled have also formed the basis of certain elaborate theories
which make opposition the basis of pain; these fail, how-
ever, in many respects, and especially in making clear the
rationale of pleasure production.

D (p. 182 ff.). Consideration of the pleasures obtained from
bodily exercise has given rise to a very large number of
theories which in one form or another connect pain with
actions dangerous to the system and pleasures with actions
healthful to the system. There are, however, so many excep-
tions to the rules laid down, so many pains that are whole-
some to the system and so many pleasures that are hurtful,
that these theories have never been felt to be satisfactory,
those which appear to cover the around most fully being
found to be illogical in detail.

Our review of these theories emphasises certain facts
which it is well to consider (p. 190 ff.). In the first place, we
find it generally conceded that all pleasures are of the
same nature, and that all pains are likewise of the same
nature, and that pleasures and pains are closely related.

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