Objection 1: It 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 2: Further, 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 3: Further, 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 contrary, It 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 that, As already stated (A), 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 1: It 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 2: These 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 3: Anger by reason of its keenness, as stated above (FS, Q , AA,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.