Whether it is against the natural law to have several wives?

❌ Objection 1 : It would seem that it is not against the natural law to have several wives. For custom does not prejudice the law of nature. But "it was not a sin" to have several wives "when this was the custom," according to Augustine (De Bono Conjug. xv) as quoted in the text (Sent. iv, D, 33). Therefore it is not contrary to the natural law to have several wives.

❌ Objection 2 : Further, whoever acts in opposition to the natural law, disobeys a commandment, for the law of nature has its commandments even as the written law has. Now Augustine says (De Bono Conjug. xv; De Civ. Dei xv, 38) that "it was not contrary to a commandment" to have several wives, "because by no law was it forbidden." Therefore it is not against the natural law to have several wives.

❌ Objection 3 : Further, marriage is chiefly directed to the begetting of offspring. But one man may get children of several women, by causing them to be pregnant. Therefore It is not against the natural law to have several wives.

❌ Objection 4 : Further, "Natural right is that which nature has taught all animals," as stated at the beginning of the Digests (1, i, ff. De just. et jure). Now nature has not taught all animals that one male should be united to but one female, since with many animals the one male is united to several females. Therefore it is not against the natural law to have several wives.

❌ Objection 5 : Further, according to the Philosopher (De Gener. Animal. i, 20), in the begetting of offspring the male is to the female as agent to patient, and as the craftsman is to his material. But it is not against the order of nature for one agent to act on several patients, or for one craftsman to work in several materials. Therefore neither is it contrary to the law of nature for one husband to have many wives.

❌ Objection 6 : On the contrary, That which was instilled into man at the formation of human nature would seem especially to belong to the natural law. Now it was instilled into him at the very formation of human nature that one man should have one wife, according to Gn. 2:24, "They shall be two in one flesh." Therefore it is of natural law.

❌ Objection 7 : Further, it is contrary to the law of nature that man should bind himself to the impossible, and that what is given to one should be given to another. Now when a man contracts with a wife, he gives her the power of his body, so that he is bound to pay her the debt when she asks. Therefore it is against the law of nature that he should afterwards give the power of his body to another, because it would be impossible for him to pay both were both to ask at the same time.

❌ Objection 8 : Further, "Do not to another what thou wouldst not were done to thyself" [*Cf. Tobias 4:16] is a precept of the natural law. But a husband would by no means be willing for his wife to have another husband. Therefore he would be acting against the law of nature, were he to have another wife in addition.

❌ Objection 9 : Further, whatever is against the natural desire is contrary to the natural law. Now a husband's jealousy of his wife and the wife's jealousy of her husband are natural, for they are found in all. Therefore, since jealousy is "love impatient of sharing the beloved," it would seem to be contrary to the natural law that several wives should share one husband.