Whether affinity is a cause of affinity?

❌ Objection 1 : It would seem that affinity also is a cause of affinity. For Pope Julius I says (cap. Contradicimus 35, qu. iii): "No man may marry his wife's surviving blood-relation": and it is said in the next chapter (cap. Porro duorum) that "the wives of two cousins are forbidden to marry, one after the other, the same husband." But this is only on account of affinity being contracted through union with a person related by affinity. Therefore affinity is a cause of affinity.

❌ Objection 2 : Further, carnal intercourse makes persons akin even as carnal procreation, since the degrees of affinity and consanguinity are reckoned equally. But consanguinity causes affinity. Therefore affinity does also.

❌ Objection 3 : Further, things that are the same with one and the same are the same with one another. But the wife contracts the same relations with all her husband's kindred. Therefore all her husband's kindred are made one with all who are related by affinity to the wife, and thus affinity is the cause of affinity.

❌ Objection 4 : On the contrary, If affinity is caused by affinity a man who has connection with two women can marry neither of them, because then the one would be related to the other by affinity. But this is false. Therefore affinity does not cause affinity.

❌ Objection 5 : Further, if affinity arose out of affinity a man by marrying another man's widow would contract affinity with all her first husband's kindred, since she is related to them by affinity. But this cannot be the case because he would become especially related by affinity to her deceased husband. Therefore, etc.

❌ Objection 6 : Further, consanguinity is a stronger tie than affinity. But the blood-relations of the wife do not become blood-relations of the husband. Much less, therefore, does affinity to the wife cause affinity to her blood-relations, and thus the same conclusion follows.