Whether six species are fittingly assigned to lust?

❌ Objection 1 : It would seem that six species are unfittingly assigned to lust, namely, "simple fornication, adultery, incest, seduction, rape, and the unnatural vice." For diversity of matter does not diversify the species. Now the aforesaid division is made with regard to diversity of matter, according as the woman with whom a man has intercourse is married or a virgin, or of some other condition. Therefore it seems that the species of lust are diversified in this way.

❌ Objection 2 : Further, seemingly the species of one vice are not differentiated by things that belong to another vice. Now adultery does not differ from simple fornication, save in the point of a man having intercourse with one who is another's, so that he commits an injustice. Therefore it seems that adultery should not be reckoned a species of lust.

❌ Objection 3 : Further, just as a man may happen to have intercourse with a woman who is bound to another man by marriage, so may it happen that a man has intercourse with a woman who is bound to God by vow. Therefore sacrilege should be reckoned a species of lust, even as adultery is.

❌ Objection 4 : Further, a married man sins not only if he be with another woman, but also if he use his own wife inordinately. But the latter sin is comprised under lust. Therefore it should be reckoned among the species thereof.

❌ Objection 5 : Further, the Apostle says (2 Cor. 12:21): "Lest again, when I come, God humble me among you, and I mourn many of them /that sinned before, and have not done penance for the uncleanness and fornication and lasciviousness that they have committed." Therefore it seems that also uncleanness and lasciviousness should be reckoned species of lust, as well as fornication.

❌ Objection 6 : Further, the thing divided is not to be reckoned among its parts. But lust is reckoned together with the aforesaid: for it is written (Gal. 5:19): "The works of the flesh are manifest, which are fornication, uncleanness, immodesty, lust [Douay: 'luxury']." Therefore it seems that fornication is unfittingly reckoned a species of lust.