Thomas Aquinas

“ For as far as we who feel pleasure are concerned, change is pleasant to us because our nature is changeable: for which reason that which is suitable to us at one time is not suitable at another; thus to warm himself at a fire is suitable to man in winter but not in summer. Again, on the part of the pleasing good which is united to us, change is pleasant. Because the continued action of an agent increases its effect: thus the longer a person remains near the fire, the more he is warmed and dried. ”

“ Wonder gives pleasure, not because it implies ignorance, but in so far as it includes the desire of learning the cause, and in so far as the wonderer learns something new, i.e. that the cause is other than he had thought it to be. ”

“ Because sadness, as actually existing, causes pleasure, inasmuch as it brings to mind that which is loved, the absence of which causes sadness; and yet the mere thought of it gives pleasure. The recollection of sadness becomes a cause of pleasure, on account of the deliverance which ensued: because absence of evil is looked upon as something good; wherefore so far as a man thinks that he has been delivered from that which caused him sorrow and pain, so much reason has he to rejoice. ”

“ To contradict and to scold can give pleasure in two ways. First, as making man imagine himself to be wise and excellent; since it belongs to wise men and elders to reprove and to scold. Secondly, in so far as by scolding and reproving, one does good to another: for this gives one pleasure, as stated above. It is pleasant to an angry man to punish, in so far as he thinks himself to be removing an apparent slight, which seems to be due to a previous hurt: for when a man is hurt by another, he seems to be slighted thereby ”

“ Now wonder is a kind of desire for knowledge; a desire which comes to man when he sees an effect of which the cause either is unknown to him, or surpasses his knowledge or faculty of understanding. Consequently wonder is a cause of pleasure, in so far as it includes a hope of getting the knowledge which one desires to have. For this reason whatever is wonderful is pleasing, for instance things that are scarce. Also, representations of things, even of those which are not pleasant in themselves, give rise to pleasure ”

“ Now, since human power is finite, operation is proportionate thereto according to a certain measure. Wherefore if it exceed that measure, it will be no longer proportionate or pleasant, but, on the contrary, painful and irksome. ”

“ And as love is for something good, while admiration is for something great, so it is pleasant to be loved and admired by others, inasmuch as a man thus becomes aware of his own goodness or greatness, through their giving pleasure to others. Thirdly, from the fact that another's actions, if they be good, are reckoned as one's own good, by reason of the power of love, which makes a man to regard his friend as one with himself. ”

“ Wherefore all those games in which there is a striving for the mastery, and a possibility of winning it, afford the greatest pleasure: and speaking generally all contests, in so far as they admit hope of victory. ”

“ Another principle is man's habitual inclination to do good, by reason of which doing good becomes connatural to him: for which reason the liberal man takes pleasure in giving to others. The third principle is the motive: for instance when a man is moved by one whom he loves, to do good to someone: for whatever we do or suffer for a friend is pleasant, because love is the principal cause of pleasure.
Reply to Objection 1: Spending gives pleasure as showing forth one's good. But in so far as it empties us of our own good it may be a cause of sadness ”

“ Thou wouldst not have the syllables stay, but fly away, that others may come, and thou hear the whole. And so whenever any one thing is made up of many, all of which do not exist together, all would please collectively more than they do severally, if all could be perceived collectively. ”

“ Nothing prevents the same thing, in different ways, being the cause of contraries. And so hope, inasmuch as it implies a present appraising of a future good, causes pleasure; whereas, inasmuch as it implies absence of that good, it causes affliction.
Reply to Objection 3: Love and concupiscence also cause pleasure. For everything that is loved becomes pleasing to the lover, since love is a kind of union or connaturalness of lover and beloved. ”

“ If therefore there be any thing, whose nature is unchangeable; the natural mode of whose being cannot be exceeded by the continuation of any pleasing object; and which can behold the whole object of its delight at once---to such a one change will afford no delight. ”

“ On the part of the knowledge itself (change becomes pleasant) , because man desires to know something whole and perfect: when therefore a thing cannot be apprehended all at once as a whole, change in such a thing is pleasant, so that one part may pass and another succeed, and thus the whole be perceived. ”

“ Now the natural mode of being consists in a certain measure; and therefore when the continued presence of a pleasant object exceeds the measure of one's natural mode of being, the removal of that object becomes pleasant. ”

“ Now that which is being moved towards something has it not as yet; but, so to speak, is being generated in its regard, forasmuch as generation or corruption are united to every movement, as stated in Phys. ”