Thomas Aquinas

“ For the proper object of sorrow is "one's own evil." Hence sorrow may be concerned for an object foreign to it either through one's being sorry for an evil that is not one's own; and thus we have "pity" which is sorrow for another's evil, considered, however, as one's own: or through one's being sorry for something that is neither evil nor one's own, but another's good, considered, however, as one's own evil: and thus we have "envy." The proper effect of sorrow consists in a certain "flight of the appetite." ”

“ The reason is because sorrow is of itself contrary to pleasure in a contrary object: thus pleasure in heat is contrary to sorrow caused by cold. But there is no contrary to the object of contemplation: because contraries, as apprehended by the mind, are not contrary, but one is the means of knowing the other. Wherefore, properly speaking, there cannot be a sorrow contrary to the pleasure of contemplation. ”

“ But movement from without is intensified by the very opposition: because each thing strives in its own way to resist anything contrary to it, as aiming at its own preservation. Hence violent movement is intense at first, and slackens towards the end. Now the movement of the appetitive faculty is from within: since it tends from the soul to the object. Consequently pleasure is, of itself, more to be sought than sorrow is to be shunned. But the movement of the sensitive faculty is from without, as it were from the object of the soul. Consequently the more contrary a thing is the more it is felt. ”

“ Another reason is because the good, which is the object of pleasure, is sought for its own sake: whereas the evil, which is the object of sorrow, is to be shunned as being a privation of good: and that which is by reason of itself is stronger than that which is by reason of something else. ”

“ And just as that pleasure which is caused by an exterior apprehension, is called pleasure but not joy; so too that pain which is caused by an exterior apprehension, is called pain indeed but not sorrow. Accordingly sorrow is a species of pain, as joy is a species of pleasure. ”

“ The "sorrow which is according to God," is not caused by the very act of intellectual contemplation, but by something which the mind contemplates: viz. by sin, which the mind considers as contrary to the love of God.
Reply to Objection 2: Things which are contrary according to nature are not contrary according as they exist in the mind: for things that are contrary in reality are not contrary in the order of thought; indeed rather is one contrary the reason for knowing the other. Hence one and the same science considers contraries. ”

“ Because inward pain is not only greater than outward pain, it is also more universal: since whatever is repugnant to the body, can be repugnant to the interior appetite; and whatever is apprehended by sense may be apprehended by imagination and reason, but not conversely. Hence in the passage quoted above it is said expressively: "Sadness of the heart is every wound," because even the pains of outward wounds are comprised in the interior sorrows of the heart. ”

“ Since, however, the human mind, in contemplation, makes use of the sensitive powers of apprehension, to whose acts weariness is incidental; therefore some affliction or pain is indirectly mingled with contemplation. ”

“ Because by the mere fact that man mourns for his sins, or for the delay of glory, he merits the consolation of eternity. In like manner a man merits it when he shrinks not from hardships and straits in order to obtain it. ”

“ Such an addition does not make true species of the genus, according to the usual sense in which we speak of genera and species. But sometimes a thing is said to be a species of a certain genus, through having something foreign to that genus indeed, but to which the notion of that genus is applicable: thus a live coal or a flame is said to be a species of fire, because in each of them the nature of fire is applied to a foreign matter. In like manner we speak of astronomy and perspective as being species of mathematics, inasmuch as the principles of mathematics are applied to natural matter. ”

“ Nor has it any sorrow annexed to it, as bodily pleasures have, which are like remedies against certain annoyances; thus a man takes pleasure in drinking through being troubled with thirst, but when the thirst is quite driven out, the pleasure of drinking ceases also. ”

“ And the reason why torpor especially is said to deprive one of speech is because of all the external movements the voice is the best expression of the inward thought and desire, not only in men, but also in other animals, as is stated in Polit. ”