Summa Theologica II-II, q. 46: Of Folly which is Opposed to Wisdom
Article 2. Whether folly is a sin?
Objection 1It would seem that folly is not a sin. For no sin arises in us from nature. But some are fools naturally. Therefore folly is not a sin.
Objection 2Further, "Every sin is voluntary," according to Augustine (De Vera Relig. xiv). But folly is not voluntary. Therefore it is not a sin.
Objection 3Further, every sin is contrary to a Divine precept. But folly is not contrary to any precept. Therefore folly is not a sin.
On the contraryIt is written (Prov. 1:32): "The prosperity of fools shall destroy them." But no man is destroyed save for sin. Therefore folly is a sin.
I answer thatFolly, as stated above (A[1]), denotes dullness of sense in judging, and chiefly as regards the highest cause, which is the last end and the sovereign good. Now a man may in this respect contract dullness in judgment in two ways. First, from a natural indisposition, as in the case of idiots, and such like folly is no sin. Secondly, by plunging his sense into earthly things, whereby his sense is rendered incapable of perceiving Divine things, according to 1 Cor. 2:14, "The sensual man perceiveth not these things that are of the Spirit of God," even as sweet things have no savor for a man whose taste is infected with an evil humor: and such like folly is a sin.
This suffices for the Reply to the First Objection.
Reply to Objection 2Though no man wishes to be a fool, yet he wishes those things of which folly is a consequence, viz. to withdraw his sense from spiritual things and to plunge it into earthly things. The same thing happens in regard to other sins; for the lustful man desires pleasure, without which there is no sin, although he does not desire sin simply, for he would wish to enjoy the pleasure without sin.
Reply to Objection 3Folly is opposed to the precepts about the contemplation of truth, of which we have spoken above (Q[16]) when we were treating of knowledge and understanding.
Article 3. Whether folly is a daughter of lust?
Objection 1It would seem that folly is not a daughter of lust. For Gregory (Moral. xxxi, 45) enumerates the daughters of lust, among which however he makes no mention of folly. Therefore folly does not proceed from lust.
Objection 2Further, the Apostle says (1 Cor. 3:19): "The wisdom of this world is foolishness with God." Now, according to Gregory (Moral. x, 29) "the wisdom of this world consists in covering the heart with crafty devices;" and this savors of duplicity. Therefore folly is a daughter of duplicity rather than of lust.
Objection 3Further, anger especially is the cause of fury and madness in some persons; and this pertains to folly. Therefore folly arises from anger rather than from lust.
On the contraryIt is written (Prov. 7:22): "Immediately he followeth her," i.e. the harlot. . . "not knowing that he is drawn like a fool to bonds."
I answer thatAs already stated (A[2]), folly, in so far as it is a sin, is caused by the spiritual sense being dulled, so as to be incapable of judging spiritual things. Now man's sense is plunged into earthly things chiefly by lust, which is about the greatest of pleasures; and these absorb the mind more than any others. Therefore the folly which is a sin, arises chiefly from lust.
Reply to Objection 1It is part of folly that a man should have a distaste for God and His gifts. Hence Gregory mentions two daughters of lust, pertaining to folly, namely, "hatred of God" and "despair of the life to come"; thus he divides folly into two parts as it were.
Reply to Objection 2These words of the Apostle are to be understood, not causally but essentially, because, to wit, worldly wisdom itself is folly with God. Hence it does not follow that whatever belongs to worldly wisdom, is a cause of this folly.
Reply to Objection 3Anger by reason of its keenness, as stated above (FS, Q[48], AA[2],3,4), produces a great change in the nature of the body, wherefore it conduces very much to the folly which results from a bodily impediment. On the other hand the folly which is caused by a spiritual impediment, viz. by the mind being plunged into earthly things, arises chiefly from lust, as stated above.