good, but "good is
contrary to evil, and evil to good," as stated in Praedic. viii;
it seems that one pleasure is not contrary to another.

Obj. 2: Further, to one thing there is one contrary, as is proved in
_Metaph._ x, 4. But sadness is contrary to pleasure. Therefore
pleasure is not contrary to pleasure.

Obj. 3: Further, if one pleasure is contrary to another, this is only
on account of the contrariety of the things which give pleasure. But
this difference is material: whereas contrariety is a difference of
form, as stated in _Metaph._ x, 4. Therefore there is no contrariety
between one pleasure and another.

_On the contrary,_ Things of the same genus that impede one another
are contraries, as the Philosopher states (Phys. viii, 8). But some
pleasures impede one another, as stated in _Ethic._ x, 5. Therefore
some pleasures are contrary to one another.

_I answer that,_ Pleasure, in the emotions of the soul, is likened to
repose in natural bodies, as stated above (Q. 23, A. 4). Now one
repose is said to be contrary to another when they are in contrary
termini; thus, "repose in a high place is contrary to repose in a low
place" (Phys. v, 6). Wherefore it happens in the emotions of the soul
that one pleasure is contrary to another.

Reply Obj. 1: This saying of the Philosopher is to be understood of
good and evil as applied to virtues and vices: because one vice may
be contrary to another vice, whereas no virtue can be contrary to
another virtue. But in other things nothing prevents one good from
being contrary to another, such as hot and cold, of which the former
is good in relation to fire, the latter, in relation to water. And in
this way one pleasure can be contrary to another. That this is
impossible with regard to the good of virtue, is due to the fact that
virtue's good depends on fittingness in relation to some one
thing--i.e. the reason.

Reply Obj. 2: Pleasure, in the emotions of the soul, is likened to
natural repose in bodies: because its object is something suitable
and connatural, so to speak. But sadness is like a violent repose;
because its object is disagreeable to the animal appetite, just as
the place of violent repose is disagreeable to the natural appetite.
Now natural repose is contrary both to violent repose of the same
body, and to the natural repose of another, as stated in _Phys._ v,
6. Wherefore pleasure is contrary to both to another pleasure and to
sadness.

Reply Obj. 3: The th