HKB
delight, and delight sets up a thirst or desire for perfect knowledge; in which sense we may understand the words of Ecclus. 24:29: "They that drink me shall yet thirst."
On the other hand, if by thirst or desire we understand the mere intensity of the emotion, that excludes distaste, thus more than all others spiritual pleasures cause thirst or desire for themselves. Because bodily pleasures become distasteful by reason of their causing an excess in the natural mode of being, when they are increased or even when they are protracted; as is evident in the case of pleasures of the table. This is why, when a man arrives at the point of perfection in bodily pleasures, he wearies of them, and sometimes desires another kind. Spiritual pleasures, on the contrary, do not exceed the natural mode of being, but perfect nature. Hence when their point of perfection is reached, then do they afford the greatest delight: except, perchance, accidentally, in so far as the work of contemplation is accompanied by some operation of the bodily powers, which tire from protracted activity. And in this sense also we may understand those words of Ecclus. 24:29: "They that drink me shall yet thirst": for, even of the angels, who know God perfectly, and delight in Him, it is written (1 Pet. 1:12) that they "desire to look at Him."
Lastly, if we consider pleasure, not as existing in reality, but as existing in the memory, thus it has of itself a natural tendency to cause thirst and desire for itself: when, to wit, man returns to that disposition, in which he was when he experienced the pleasure that is past. But if he be changed from that disposition, the memory of that pleasure does not give him pleasure, but distaste: for instance, the memory of food in respect of a man who has eaten to repletion.
Reply Obj. 1: When pleasure is perfect, then it includes complete rest; and the movement of desire, tending to what was not possessed, ceases. But when it is imperfect, then the desire, tending to what was not possessed, does not cease altogether.
Reply Obj. 2: That which is possessed imperfectly, is possessed in one respect, and in another respect is not possessed. Consequently it may be the object of desire and pleasure at the same time.
Reply Obj. 3: Pleasures cause distaste in one way, desire in another, as stated above.
THIRD ARTICLE [I-II, Q. 33, Art. 3]
Whether Pleasure Hinders the Use of Reason?
Objection 1: It would seem that pleasure does not hinder the use of reason. Because repose facilitates very much the due use of reason: wherefore the Philosopher says (Phys. vii, 3) that "while we sit and rest, the soul is inclined to knowledge and prudence"; and it is written (Wis. 8:16): "When I go into my house, I shall repose myself with her," i.e. wisdom. But pleasure is a kind of repose. Therefore it helps rather than hinders the use of reason.
Obj. 2: Further, things which are not in the same subject though they be contraries, do not hinder one another. But pleasure is in the appetitive faculty, while the use of reason is in the apprehensive power. Therefore pleasure does not hinder the use of reason.
Obj. 3: Further, that which is hindered by another, seems to be moved, as it were, thereby. But the use of an apprehensive power moves pleasure rather than is moved by it: because it is the cause of pleasure. Therefore pleasure does not hinder the use of reason.
On the contrary, The Philosopher says (Ethic. vi, 5), that "pleasure destroys the estimate of prudence."