Thomas Aquinas

“ The pleasures of wicked men are not a cause of sorrow while they are enjoyed, but afterwards: that is to say, in so far as wicked men repent of those things in which they took pleasure. This sorrow is healed by contrary pleasures. ”

“ Reply to Objection 1: "He that addeth knowledge, addeth sorrow," either on account of the difficulty and disappointment in the search for truth; or because knowledge makes man acquainted with many things that are contrary to his will. Accordingly, on the part of the things known, knowledge causes sorrow: but on the part of the contemplation of truth, it causes pleasure. ”

“ I answer that, Tears and groans naturally assuage sorrow: and this for two reasons. First, because a hurtful thing hurts yet more if we keep it shut up, because the soul is more intent on it: whereas if it be allowed to escape, the soul's intention is dispersed as it were on outward things, so that the inward sorrow is lessened. ”

“ Consequently in movements of the appetite pleasure is to sorrow, what, in bodies, repose is to weariness, which is due to a non-natural transmutation; for sorrow itself implies a certain weariness or ailing of the appetitive faculty. Therefore just as all repose of the body brings relief to any kind of weariness, ensuing from any non-natural cause; so every pleasure brings relief by assuaging any kind of sorrow, due to any cause whatever. ”

“ This is why men, burdened with sorrow, make outward show of their sorrow, by tears or groans or even by words, their sorrow is assuaged. Secondly, because an action, that befits a man according to his actual disposition, is always pleasant to him. Now tears and groans are actions befitting a man who is in sorrow or pain ”