Summa Th. I-II EN Qu.32 a.6

Whether doing good to another is a cause of pleasure?

Objection: 1. It would seem that doing good to another is not a cause of pleasure. Because pleasure is caused by one's obtaining one's proper good, as stated above (Articles [1],5; Question [31], Article [1]). But doing good pertains not to the obtaining but to the spending of one's proper good. Therefore it seems to be the cause of sadness rather than of pleasure.
2. Further, the Philosopher says (Ethic. iv, 1) that "illiberality is more connatural to man than prodigality." Now it is a mark of prodigality to do good to others; while it is a mark of illiberality to desist from doing good. Since therefore everyone takes pleasure in a connatural operation, as stated in Ethic. vii, 14 and x, 4, it seems that doing good to others is not a cause of pleasure.
3. Further, contrary effects proceed from contrary causes. But man takes a natural pleasure in certain kinds of ill-doing, such as overcoming, contradicting or scolding others, or, if he be angry, in punishing them, as the Philosopher says (Rhet. i, 11). Therefore doing good to others is a cause of sadness rather than pleasure.

On the contrary The Philosopher says (Polit. ii, 2) that "it is most pleasant to give presents or assistance to friends and strangers."
I answer that Doing good to another may give pleasure in three ways. First, in consideration of the effect, which is the good conferred on another. In this respect, inasmuch as through being united to others by love, we look upon their good as being our own, we take pleasure in the good we do to others, especially to our friends, as in our own good. Secondly, in consideration of the end; as when a man, from doing good to another, hopes to get some good for himself, either from God or from man: for hope is a cause of pleasure. Thirdly, in consideration of the principle: and thus, doing good to another, can give pleasure in respect of a threefold principle. One is the faculty of doing good: and in this regard, doing good to another becomes pleasant, in so far as it arouses in man an imagination of abundant good existing in him, whereof he is able to give others a share. Wherefore men take pleasure in their children, and in their own works, as being things on which they bestow a share of their own good. 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; for instance when it is excessive.
2. Prodigality is an excessive spending, which is unnatural: wherefore prodigality is said to be contrary to nature.
3. To overcome, to contradict, and to punish, give pleasure, not as tending to another's ill, but as pertaining to one's own good, which man loves more than he hates another's ill. For it is naturally pleasant to overcome, inasmuch as it makes a man to appreciate his own superiority. 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. 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; and therefore he wishes to be quit of this slight by paying back the hurt. And thus it is clear that doing good to another may be of itself pleasant: whereas doing evil to another is not pleasant, except in so far as it seems to affect one's own good.

Whether likeness is a cause of pleasure?

Objection: 1. It would seem that likeness is not a cause of pleasure. Because ruling and presiding seem to imply a certain unlikeness. But "it is natural to take pleasure in ruling and presiding," as stated in Rhetor. i, 11. Therefore unlikeness, rather than likeness, is a cause of pleasure.
2. Further, nothing is more unlike pleasure than sorrow. But those who are burdened by sorrow are most inclined to seek pleasures, as the Philosopher says (Ethic. vii, 14). Therefore unlikeness, rather than likeness, is a cause of pleasure.
3. Further, those who are satiated with certain delights, derive not pleasure but disgust from them; as when one is satiated with food. Therefore likeness is not a cause of pleasure.

On the contrary Likeness is a cause of love, as above stated (Question [27], Article [3]): and love is the cause of pleasure. Therefore likeness is a cause of pleasure.
I answer that Likeness is a kind of unity; hence that which is like us, as being one with us, causes pleasure; just at it causes love, as stated above (Question [27], Article [3]). And if that which is like us does not hurt our own good, but increase it, it is pleasurable simply; for instance one man in respect of another, one youth in relation to another. But if it be hurtful to our own good, thus accidentally it causes disgust or sadness, not as being like and one with us, but as hurtful to that which is yet more one with us.
Now it happens in two ways that something like is hurtful to our own good. First, by destroying the measure of our own good, by a kind of excess; because good, especially bodily good, as health, is conditioned by a certain measure: wherefore superfluous good or any bodily pleasure, causes disgust. Secondly, by being directly contrary to one's own good: thus a potter dislikes other potters, not because they are potters, but because they deprive him of his own excellence or profits, which he seeks as his own good.

Reply to Objection: 1. Since ruler and subject are in communion with one another, there is a certain likeness between them: but this likeness is conditioned by a certain superiority, since ruling and presiding pertain to the excellence of a man's own good: because they belong to men who are wise and better than others; the result being that they give man an idea of his own excellence. Another reason is that by ruling and presiding, a man does good to others, which is pleasant.
2. That which gives pleasure to the sorrowful man, though it be unlike sorrow, bears some likeness to the man that is sorrowful: because sorrows are contrary to his own good. Wherefore the sorrowful man seeks pleasure as making for his own good, in so far as it is a remedy for its contrary. And this is why bodily pleasures, which are contrary to certain sorrows, are more sought than intellectual pleasures, which have no contrary sorrow, as we shall state later on (Question [35], Article [5]). And this explains why all animals naturally desire pleasure: because animals ever work through sense and movement. For this reason also young people are most inclined to seek pleasures; on account of the many changes to which they are subject, while yet growing. Moreover this is why the melancholic has a strong desire for pleasures, in order to drive away sorrow: because his "body is corroded by a base humor," as stated in Ethic. vii, 14.
3. Bodily goods are conditioned by a certain fixed measure: wherefore surfeit of such things destroys the proper good, and consequently gives rise to disgust and sorrow, through being contrary to the proper good of man.

Whether wonder is a cause of pleasure?

Objection: 1. It would seem that wonder is not a cause of pleasure. Because wonder is the act of one who is ignorant of the nature of something, as Damascene says. But knowledge, rather than ignorance, is a cause of pleasure. Therefore wonder is not a cause of pleasure.
2. Further, wonder is the beginning of wisdom, being as it were, the road to the search of truth, as stated in the beginning of Metaph. i, 2. But "it is more pleasant to think of what we know, than to seek what we know not," as the Philosopher says (Ethic. x, 7): since in the latter case we encounter difficulties and hindrances, in the former not; while pleasure arises from an operation which is unhindered, as stated in Ethic. vii, 12,13. Therefore wonder hinders rather than causes pleasure.
3. Further, everyone takes pleasure in what he is accustomed to: wherefore the actions of habits acquired by custom, are pleasant. But "we wonder at what is unwonted," as Augustine says (Tract. xxiv in Joan.). Therefore wonder is contrary to the cause of pleasure.

On the contrary The Philosopher says (Rhet. i, 11) that wonder is the cause of pleasure.
I answer that It is pleasant to get what one desires, as stated above (Question [23], Article [4]): and therefore the greater the desire for the thing loved, the greater the pleasure when it is attained: indeed the very increase of desire brings with it an increase of pleasure, according as it gives rise to the hope of obtaining that which is loved, since it was stated above (Article [3], ad 3) that desire resulting from hope is a cause of pleasure. 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; for the soul rejoices in comparing one thing with another, because comparison of one thing with another is the proper and connatural act of the reason, as the Philosopher says (Poet. iv). This again is why "it is more delightful to be delivered from great danger, because it is something wonderful," as stated in Rhetor. i, 11.

Reply to Objection: 1. 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. [*According to another reading:---that he is other than he thought himself to be.]
2. Pleasure includes two things; rest in the good, and perception of this rest. As to the former therefore, since it is more perfect to contemplate the known truth, than to seek for the unknown, the contemplation of what we know, is in itself more pleasing than the research of what we do not know. Nevertheless, as to the second, it happens that research is sometimes more pleasing accidentally, in so far as it proceeds from a greater desire: for greater desire is awakened when we are conscious of our ignorance. This is why man takes the greatest pleasure in finding or learning things for the first time.
3. It is pleasant to do what we are wont to do, inasmuch as this is connatural to us, as it were. And yet things that are of rare occurrence can be pleasant, either as regards knowledge, from the fact that we desire to know something about them, in so far as they are wonderful; or as regards action, from the fact that "the mind is more inclined by desire to act intensely in things that are new," as stated in Ethic. x, 4, since more perfect operation causes more perfect pleasure.


We must now consider the effects of pleasure; and under this head there are four points of inquiry:

(1) Whether expansion is an effect of pleasure?

(2) Whether pleasure causes thirst or desire for itself?

(3) Whether pleasure hinders the use of reason?

(4) Whether pleasure perfects operation?

Whether expansion is an effect of pleasure?

Objection: 1. It would seem that expansion is not an effect of pleasure. For expansion seems to pertain more to love, according to the Apostle (2Co 6,11): "Our heart is enlarged." Wherefore it is written (Ps 118,96) concerning the precept of charity: "Thy commandment is exceeding broad." But pleasure is a distinct passion from love. Therefore expansion is not an effect of pleasure.
2. Further, when a thing expands it is enabled to receive more. But receiving pertains to desire, which is for something not yet possessed. Therefore expansion seems to belong to desire rather than to pleasure.
3. Further, contraction is contrary to expansion. But contraction seems to belong to pleasure, for the hand closes on that which we wish to grasp firmly: and such is the affection of appetite in regard to that which pleases it. Therefore expansion does not pertain to pleasure.

On the contrary In order to express joy, it is written (Is 60,5): "Thou shall see and abound, thy heart shall wonder and be enlarged." Moreover pleasure is called by the name of "laetitia" as being derived from "dilatatio" [expansion], as stated above (Question [31], Article [3], ad 3).
I answer that Breadth [latitudo] is a dimension of bodily magnitude: hence it is not applied to the emotions of the soul, save metaphorically. Now expansion denotes a kind of movement towards breadth; and it belongs to pleasure in respect of the two things requisite for pleasure. One of these is on the part of the apprehensive power, which is cognizant of the conjunction with some suitable good. As a result of this apprehension, man perceives that he has attained a certain perfection, which is a magnitude of the spiritual order: and in this respect man's mind is said to be magnified or expanded by pleasure. The other requisite for pleasure is on the part of the appetitive power, which acquiesces in the pleasurable object, and rests therein, offering, as it were, to enfold it within itself. And thus man's affection is expanded by pleasure, as though it surrendered itself to hold within itself the object of its pleasure.

Reply to Objection: 1. In metaphorical expressions nothing hinders one and the same thing from being attributed to different things according to different likenesses. And in this way expansion pertains to love by reason of a certain spreading out, in so far as the affection of the lover spreads out to others, so as to care, not only for his own interests, but also for what concerns others. On the other hand expansion pertains to pleasure, in so far as a thing becomes more ample in itself so as to become more capacious.
2. Desire includes a certain expansion arising from the imagination of the thing desired; but this expansion increases at the presence of the pleasurable object: because the mind surrenders itself more to that object when it is already taking pleasure in it, than when it desires it before possessing it; since pleasure is the end of desire.
3. He that takes pleasure in a thing holds it fast, by clinging to it with all his might: but he opens his heart to it that he may enjoy it perfectly.

Whether pleasure causes thirst or desire for itself?

Objection: 1. It would seem that pleasure does not cause desire for itself. Because all movement ceases when repose is reached. But pleasure is, as it were, a certain repose of the movement of desire, as stated above (Question [23], Article [4]; Question [25], Article [2]). Therefore the movement of desire ceases when pleasure is reached. Therefore pleasure does not cause desire.
2. Further, a thing does not cause its contrary. But pleasure is, in a way, contrary to desire, on the part of the object: since desire regards a good which is not yet possessed, whereas pleasure regards the good that is possessed. Therefore pleasure does not cause desire for itself.
3. Further, distaste is incompatible with desire. But pleasure often causes distaste. Therefore it does not cause desire.

On the contrary Our Lord said (Jn 4,13): "Whosoever drinketh of this water, shall thirst again": where, according to Augustine (Tract. xv in Joan.), water denotes pleasures of the body.
I answer that Pleasure can be considered in two ways; first, as existing in reality; secondly, as existing in the memory. Again thirst, or desire, can be taken in two ways; first, properly, as denoting a craving for something not possessed; secondly, in general, as excluding distaste.Considered as existing in reality, pleasure does not of itself cause thirst or desire for itself, but only accidentally; provided we take thirst or desire as denoting a craving for some thing not possessed: because pleasure is an emotion of the appetite in respect of something actually present. But it may happen that what is actually present is not perfectly possessed: and this may be on the part of the thing possessed, or on the part of the possessor. On the part of the thing possessed, this happens through the thing possessed not being a simultaneous whole; wherefore one obtains possession of it successively, and while taking pleasure in what one has, one desires to possess the remainder: thus if a man is pleased with the first part of a verse, he desires to hear the second part, as Augustine says (Confess. iv, 11). In this way nearly all bodily pleasures cause thirst for themselves, until they are fully realized, because pleasures of this kind arise from some movement: as is evident in pleasures of the table. On the part of the possessor, this happens when a man possesses a thing which is perfect in itself, yet does not possess it perfectly, but obtains possession of it little by little. Thus in this life, a faint perception of Divine knowledge affords us delight, and delight sets up a thirst or desire for perfect knowledge; in which sense we may understand the words of Si 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 Si 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 (1P 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 to Objection: 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.
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.
3. Pleasures cause distaste in one way, desire in another, as stated above.

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 (Sg 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.
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.
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."
I answer that As is stated in Ethic. x, 5, "appropriate pleasures increase activity . . . whereas pleasures arising from other sources are impediments to activity." Accordingly there is a certain pleasure that is taken in the very act of reason, as when one takes pleasure in contemplating or in reasoning: and such pleasure does not hinder the act of reason, but helps it; because we are more attentive in doing that which gives us pleasure, and attention fosters activity.On the other hand bodily pleasures hinder the use of reason in three ways. First, by distracting the reason. Because, as we have just observed, we attend much to that which pleases us. Now when the attention is firmly fixed on one thing, it is either weakened in respect of other things, or it is entirely withdrawn from them; and thus if the bodily pleasure be great, either it entirely hinders the use of reason, by concentrating the mind's attention on itself; or else it hinders it considerably. Secondly, by being contrary to reason. Because some pleasures, especially those that are in excess, are contrary to the order of reason: and in this sense the Philosopher says that "bodily pleasures destroy the estimate of prudence, but not the speculative estimate," to which they are not opposed, "for instance that the three angles of a triangle are together equal to two right angles." In the first sense, however, they hinder both estimates. Thirdly, by fettering the reason: in so far as bodily pleasure is followed by a certain alteration in the body, greater even than in the other passions, in proportion as the appetite is more vehemently affected towards a present than towards an absent thing. Now such bodily disturbances hinder the use of reason; as may be seen in the case of drunkards, in whom the use of reason is fettered or hindered.

Reply to Objection: 1. Bodily pleasure implies indeed repose of the appetite in the object of pleasure; which repose is sometimes contrary to reason; but on the part of the body it always implies alteration. And in respect of both points, it hinders the use of reason.
2. The powers of the appetite and of apprehension are indeed distinct parts, but belonging to the one soul. Consequently when the soul is very intent on the action of one part, it is hindered from attending to a contrary act of the other part.
3. The use of reason requires the due use of the imagination and of the other sensitive powers, which are exercised through a bodily organ. Consequently alteration in the body hinders the use of reason, because it hinders the act of the imagination and of the other sensitive powers.

Whether pleasure perfects operation?

Objection: 1. It would seem that pleasure does not perfect operation. For every human operation depends on the use of reason. But pleasure hinders the use of reason, as stated above (Article [3]). Therefore pleasure does not perfect, but weakens human operation.
2. Further, nothing perfects itself or its cause. But pleasure is an operation (Ethic. vii, 12; x, 4), i.e. either in its essence or in its cause. Therefore pleasure does not perfect operation.
3. Further, if pleasure perfects operation, it does so either as end, or as form, or as agent. But not as end; because operation is not sought for the sake of pleasure, but rather the reverse, as stated above (Question [4], Article [2]): nor as agent, because rather is it the operation that causes pleasure: nor again as form, because, according to the Philosopher (Ethic. x, 4), "pleasure does not perfect operation, as a habit does." Therefore pleasure does not perfect operation.

On the contrary The Philosopher says (Ethic. x, 4) that "pleasure perfects operation."
I answer that Pleasure perfects operation in two ways. First, as an end: not indeed according as an end is that on "account of which a thing is"; but according as every good which is added to a thing and completes it, can be called its end. And in this sense the Philosopher says (Ethic. x, 4) that "pleasure perfects operation . . . as some end added to it": that is to say, inasmuch as to this good, which is operation, there is added another good, which is pleasure, denoting the repose of the appetite in a good that is presupposed. Secondly, as agent; not indeed directly, for the Philosopher says (Ethic. x, 4) that "pleasure perfects operation, not as a physician makes a man healthy, but as health does": but it does so indirectly; inasmuch as the agent, through taking pleasure in his action, is more eagerly intent on it, and carries it out with greater care. And in this sense it is said in Ethic. x, 5 that "pleasures increase their appropriate activities, and hinder those that are not appropriate."

Reply to Objection: 1. It is not every pleasure that hinders the act of reason, but only bodily pleasure; for this arises, not from the act of reason, but from the act of the concupiscible faculty, which act is intensified by pleasure. On the contrary, pleasure that arises from the act of reason, strengthens the use of reason.
2. As stated in Phys. ii, 3 two things may be causes of one another, if one be the efficient, the other the final cause. And in this way, operation is the efficient cause of pleasure, while pleasure perfects operation by way of final cause, as stated above.
3. The Reply to the Third Objection is evident for what has been said.


We must now consider the goodness and malice of pleasures: under which head there are four points of inquiry:

(1) Whether every pleasure is evil?

(2) If not, whether every pleasure is good?

(3) Whether any pleasure is the greatest good?

(4) Whether pleasure is the measure or rule by which to judge of moral good and evil?

Whether every pleasure is evil?

Objection: 1. It would seem that every pleasure is evil. For that which destroys prudence and hinders the use of reason, seems to be evil in itself: since man's good is to be "in accord with reason," as Dionysius says (Div. Nom. iv). But pleasure destroys prudence and hinders the use of reason; and so much the more, as the pleasure is greater: wherefore "in sexual pleasures," which are the greatest of all, "it is impossible to understand anything," as stated in Ethic. vii, 11. Moreover, Jerome says in his commentary on Matthew [*Origen, Hom. vi in Num.] that "at the time of conjugal intercourse, the presence of the Holy Ghost is not vouchsafed, even if it be a prophet that fulfils the conjugal duty." Therefore pleasure is evil in itself; and consequently every pleasure is evil.
2. Further, that which the virtuous man shuns, and the man lacking in virtue seeks, seems to be evil in itself, and should be avoided; because, as stated in Ethic. x, 5 "the virtuous man is a kind of measure and rule of human actions"; and the Apostle says (1Co 2,15): "The spiritual man judgeth all things." But children and dumb animals, in whom there is no virtue, seek pleasure: whereas the man who is master of himself does not. Therefore pleasures are evil in themselves and should be avoided.
3. Further, "virtue and art are concerned about the difficult and the good" (Ethic. ii, 3). But no art is ordained to pleasure. Therefore pleasure is not something good.

On the contrary It is written (Ps 36,4): "Delight in the Lord." Since, therefore, Divine authority leads to no evil, it seems that not every pleasure is evil.
I answer that As stated in Ethic. x, 2,[3] some have maintained that all pleasure is evil. The reason seems to have been that they took account only of sensible and bodily pleasures which are more manifest; since, also in other respects, the ancient philosophers did not discriminate between the intelligible and the sensible, nor between intellect and sense (De Anima iii, 3). And they held that all bodily pleasures should be reckoned as bad, and thus that man, being prone to immoderate pleasures, arrives at the mean of virtue by abstaining from pleasure. But they were wrong in holding this opinion. Because, since none can live without some sensible and bodily pleasure, if they who teach that all pleasures are evil, are found in the act of taking pleasure; men will be more inclined to pleasure by following the example of their works instead of listening to the doctrine of their words: since, in human actions and passions, wherein experience is of great weight, example moves more than words.We must therefore say that some pleasures are good, and that some are evil. For pleasure is a repose of the appetitive power in some loved good, and resulting from some operation; wherefore we assign a twofold reason for this assertion. The first is in respect of the good in which a man reposes with pleasure. For good and evil in the moral order depend on agreement or disagreement with reason, as stated above (Question [18], Article [5]): just as in the order of nature, a thing is said to be natural, if it agrees with nature, and unnatural, if it disagrees. Accordingly, just as in the natural order there is a certain natural repose, whereby a thing rests in that which agrees with its nature, for instance, when a heavy body rests down below; and again an unnatural repose, whereby a thing rests in that which disagrees with its nature, as when a heavy body rests up aloft: so, in the moral order, there is a good pleasure, whereby the higher or lower appetite rests in that which is in accord with reason; and an evil pleasure, whereby the appetite rests in that which is discordant from reason and the law of God.The second reason can be found by considering the actions, some of which are good, some evil. Now pleasures which are conjoined to actions are more akin to those actions, than desires, which precede them in point of time. Wherefore, since the desires of good actions are good, and of evil actions, evil; much more are the pleasures of good actions good, and those of evil actions evil.

Reply to Objection: 1. As stated above (Question [33], Article [3]), it is not the pleasures which result from an act of reason, that hinder the reason or destroy prudence, but extraneous pleasures, such as the pleasures of the body. These indeed hinder the use of reason, as stated above (Question [33], Article [3]), either by contrariety of the appetite that rests in something repugnant to reason, which makes the pleasure morally bad; or by fettering the reason: thus in conjugal intercourse, though the pleasure be in accord with reason, yet it hinders the use of reason, on account of the accompanying bodily change. But in this case the pleasure is not morally evil; as neither is sleep, whereby the reason is fettered, morally evil, if it be taken according to reason: for reason itself demands that the use of reason be interrupted at times. We must add, however, that although this fettering of the reason through the pleasure of conjugal intercourse has no moral malice, since it is neither a mortal nor a venial sin; yet it proceeds from a kind of moral malice, namely, from the sin of our first parent; because, as stated in the FP, Question [98], Article [2] the case was different in the state of innocence.
2. The temperate man does not shun all pleasures, but those that are immoderate, and contrary to reason. The fact that children and dumb animals seek pleasures, does not prove that all pleasures are evil: because they have from God their natural appetite, which is moved to that which is naturally suitable to them.
3. Art is not concerned with all kinds of good, but with the making of external things, as we shall state further on (Question [57], Article [3]). But actions and passions, which are within us, are more the concern of prudence and virtue than of art. Nevertheless there is an art of making pleasure, namely, "the art of cookery and the art of making arguments," as stated in Ethic. vii, 12.

Summa Th. I-II EN Qu.32 a.6