Reply Obj. 3:  The sensibles of touch are painful, not only in so far as they are disproportionate to the apprehensive power, but also in so far as they are contrary to nature:  whereas the objects of the other senses can indeed be disproportionate to the apprehensive power, but they are not contrary to nature, save as they are subordinate to the sensibles of touch.  Consequently man alone, who is a perfectly cognizant animal, takes pleasure in the objects of the other senses for their own sake; whereas other animals take no pleasure in them save as referable to the sensibles of touch, as stated in Ethic. iii, 10.  Accordingly, in referring to the objects of the other senses, we do not speak of pain in so far as it is contrary to natural pleasure:  but rather of sorrow, which is contrary to joy.  So then if pain be taken as denoting bodily pain, which is its more usual meaning, then it is contrasted with sorrow, according to the distinction of interior and exterior apprehension; although, on the part of the objects, pleasure extends further than does bodily pain.  But if pain be taken in a wide sense, then it is the genus of sorrow, as stated above. ________________________

THIRD ARTICLE [I-II, Q. 35, Art. 3]

Whether Sorrow or Pain Is Contrary to Pleasure?

Objection 1:  It would seem that sorrow is not contrary to pleasure.  For one of two contraries is not the cause of the other.  But sorrow can be the cause of pleasure; for it is written (Matt. 5:5):  “Blessed are they that mourn, for they shall be comforted.”  Therefore they are not contrary to one another.

Obj. 2:  Further, one contrary does not denominate the other.  But to some, pain or sorrow gives pleasure:  thus Augustine says (Confess. iii, 2) that in stage-plays sorrow itself gives pleasure:  and (Confess. iv, 5) that “weeping is a bitter thing, and yet it sometimes pleases us.”  Therefore pain is not contrary to pleasure.

Obj. 3:  Further, one contrary is not the matter of the other; because contraries cannot co-exist together.  But sorrow can be the matter of pleasure; for Augustine says (De Poenit. xiii):  “The penitent should ever sorrow, and rejoice in his sorrow.”  The Philosopher too says (Ethic. ix, 4) that, on the other hand, “the evil man feels pain at having been pleased.”  Therefore pleasure and pain are not contrary to one another.

On the contrary, Augustine says (De Civ.  Dei xiv, 6) that “joy is the volition of consent to the things we wish:  and that sorrow is the volition of dissent from the things we do not wish.”  But consent and dissent are contraries.  Therefore pleasure and sorrow are contrary to one another.

I answer that, As the Philosopher says (Metaph. x, 4), contrariety is a difference in respect of a form.  Now the form or species of a passion or movement is taken from the object or term.  Consequently, since the objects of pleasure and sorrow or pain, viz. present good and present evil, are contrary to one another, it follows that pain and pleasure are contrary to one another.