--- title: "Summa Theologica, Second Half" author: "Thomas Aquinas" translator: "Fathers of the English Dominican Province" languages: [en] shelf: "Medieval" section: 94 of 935 url: https://scriptura.si/works/thomas-aquinas-summa-theologica-second-half/94/ cite: "Thomas Aquinas, tr. Fathers of the English Dominican Province, Summa Theologica, Second Half, section 94. Scriptura (scriptura.si), https://scriptura.si/works/thomas-aquinas-summa-theologica-second-half/94/" --- # Summa Theologica, Second Half *Thomas Aquinas, tr. Fathers of the English Dominican Province* Courage and temperance, the states of life, then Christ, the sacraments and the last things. ## 94. II–II · Q. 154, Art. 9: Whether incest is a determinate species of lust? Source: https://scriptura.si/works/thomas-aquinas-summa-theologica-second-half/94/ · cite a paragraph as https://scriptura.si/works/thomas-aquinas-summa-theologica-second-half/94/#p-N [¶0] Whether incest is a determinate species of lust? [¶1] Objection 1: It would seem that incest is not a determinate species of lust. For incest [*'Incestus' is equivalent to 'in-castus = 'unchaste'] takes its name from being a privation of chastity. But all kinds of lust are opposed to chastity. Therefore it seems that incest is not a species of lust, but is lust itself in general. [¶2] Objection 2: Further, it is stated in the Decretals (XXXVI, qu. 1 [*Cf. Append. Grat. ad can. Lex illa]) that "incest is intercourse between a man and a woman related by consanguinity or affinity." Now affinity differs from consanguinity. Therefore it is not one but several species of lust. [¶3] Objection 3: Further, that which does not, of itself, imply a deformity, does not constitute a determinate species of vice. But intercourse between those who are related by consanguinity or affinity does not, of itself, contain any deformity, else it would never have been lawful. Therefore incest is not a determinate species of lust. [¶4] On the contrary, The species of lust are distinguished according to the various conditions of women with whom a man has unlawful intercourse. Now incest implies a special condition on the part of the woman, because it is unlawful intercourse with a woman related by consanguinity or affinity as stated (OBJ). Therefore incest is a determinate species of lust. [¶5] I answer that, As stated above (AA 1,6) wherever we find something incompatible with the right use of venereal actions, there must needs be a determinate species of lust. Now sexual intercourse with women related by consanguinity or affinity is unbecoming to venereal union on three counts. First, because man naturally owes a certain respect to his parents and therefore to his other blood relations, who are descended in near degree from the same parents: so much so indeed that among the ancients, as Valerius Maximus relates [*Dict. Fact. Memor. ii, 1], it was not deemed right for a son to bathe with his father, lest they should see one another naked. Now from what has been said (Q 142, A 4: Q 151, A 4), it is evident that in venereal acts there is a certain shamefulness inconsistent with respect, wherefore men are ashamed of them. Wherefore it is unseemly that such persons should be united in venereal intercourse. This reason seems to be indicated (Lev. 18:7) where we read: "She is thy mother, thou shalt not uncover her nakedness," and the same is expressed further on with regard to others. [¶6] The second reason is because blood relations must needs live in close touch with one another. Wherefore if they were not debarred from venereal union, opportunities of venereal intercourse would be very frequent and thus men's minds would be enervated by lust. Hence in the Old Law [*Lev. 18] the prohibition was apparently directed specially to those persons who must needs live together. [¶7] The third reason is, because this would hinder a man from having many friends: since through a man taking a stranger to wife, all his wife's relations are united to him by a special kind of friendship, as though they were of the same blood as himself. Wherefore Augustine says (De Civ. Dei xv, 16): "The demands of charity are most perfectly satisfied by men uniting together in the bonds that the various ties of friendship require, so that they may live together in a useful and becoming amity; nor should one man have many relationships in one, but each should have one." [¶8] Aristotle adds another reason (2 Polit. ii): for since it is natural that a man should have a liking for a woman of his kindred, if to this be added the love that has its origin in venereal intercourse, his love would be too ardent and would become a very great incentive to lust: and this is contrary to chastity. Hence it is evident that incest is a determinate species of lust. [¶9] Reply to Objection 1: Unlawful intercourse between persons related to one another would be most prejudicial to chastity, both on account of the opportunities it affords, and because of the excessive ardor of love, as stated in the Article. Wherefore the unlawful intercourse between such persons is called "incest" antonomastically. [¶10] Reply to Objection 2: Persons are related by affinity through one who is related by consanguinity: and therefore since the one depends on the other, consanguinity and affinity entail the same kind of unbecomingness. [¶11] Reply to Objection 3: There is something essentially unbecoming and contrary to natural reason in sexual intercourse between persons related by blood, for instance between parents and children who are directly and immediately related to one another, since children naturally owe their parents honor. Hence the Philosopher instances a horse (De Animal. ix, 47) which covered its own mother by mistake and threw itself over a precipice as though horrified at what it had done, because some animals even have a natural respect for those that have begotten them. There is not the same essential unbecomingness attaching to other persons who are related to one another not directly but through their parents: and, as to this, becomingness or unbecomingness varies according to custom, and human or Divine law: because, as stated above (A 2), sexual intercourse, being directed to the common good, is subject to law. Wherefore, as Augustine says (De Civ. Dei xv, 16), whereas the union of brothers and sisters goes back to olden times, it became all the more worthy of condemnation when religion forbade it. ### II–II · Q. 154, Art. 10: Whether sacrilege can be a species of lust? [¶13] Whether sacrilege can be a species of lust? [¶14] Objection 1: It would seem that sacrilege cannot be a species of lust. For the same species is not contained under different genera that are not subalternated to one another. Now sacrilege is a species of irreligion, as stated above (Q 99, A 2). Therefore sacrilege cannot be reckoned a species of lust. [¶15] Objection 2: Further, the Decretals (XXXVI, qu. 1 [*Append. Grat. ad can. Lex illa]), do not place sacrilege among other sins which are reckoned species of lust. Therefore it would seem not to be a species of lust. [¶16] Objection 3: Further, something derogatory to a sacred thing may be done by the other kinds of vice, as well as by lust. But sacrilege is not reckoned a species of gluttony, or of any other similar vice. Therefore neither should it be reckoned a species of lust. [¶17] On the contrary, Augustine says (De Civ. Dei xv, 16) that "if it is wicked, through covetousness, to go beyond one's earthly bounds, how much more wicked is it through venereal lust to transgress the bounds of morals!" Now to go beyond one's earthly bounds in sacred matters is a sin of sacrilege. Therefore it is likewise a sin of sacrilege to overthrow the bounds of morals through venereal desire in sacred matters. But venereal desire pertains to lust. Therefore sacrilege is a species of lust. [¶18] I answer that, As stated above (FS, Q 18, AA 6,7), the act of a virtue or vice, that is directed to the end of another virtue or vice, assumes the latter's species: thus, theft committed for the sake of adultery, passes into the species of adultery. Now it is evident that as Augustine states (De Virgin. 8), the observance of chastity, by being directed to the worship of God, becomes an act of religion, as in the case of those who vow and keep chastity. Wherefore it is manifest that lust also, by violating something pertaining to the worship of God, belongs to the species of sacrilege: and in this way sacrilege may be accounted a species of lust. [¶19] Reply to Objection 1: Lust, by being directed to another vice as its end, becomes a species of that vice: and so a species of lust may be also a species of irreligion, as of a higher genus. [¶20] Reply to Objection 2: The enumeration referred to, includes those sins which are species of lust by their very nature: whereas sacrilege is a species of lust in so far as it is directed to another vice as its end, and may coincide with the various species of lust. For unlawful intercourse between persons mutually united by spiritual relationship, is a sacrilege after the manner of incest. Intercourse with a virgin consecrated to God, inasmuch as she is the spouse of Christ, is sacrilege resembling adultery. If the maiden be under her father's authority, it will be spiritual seduction; and if force be employed it will be spiritual rape, which kind of rape even the civil law punishes more severely than others. Thus the Emperor Justinian says [*Cod. i, iii de Episc. et Cler. 5]: "If any man dare, I will not say to rape, but even to tempt a consecrated virgin with a view to marriage, he shall be liable to capital punishment." [¶21] Reply to Objection 3: Sacrilege is committed on a consecrated thing. Now a consecrated thing is either a consecrated person, who is desired for sexual intercourse, and thus it is a kind of lust, or it is desired for possession, and thus it is a kind of injustice. Sacrilege may also come under the head of anger, for instance, if through anger an injury be done to a consecrated person. Again, one may commit a sacrilege by partaking gluttonously of sacred food. Nevertheless, sacrilege is ascribed more specially to lust which is opposed to chastity for the observance of which certain persons are specially consecrated.