Whether consanguinity is rightly defined?

❌ Objection 1 : It would seem that consanguinity is unsuitably defined by some as follows: "Consanguinity is the tie contracted between persons descending from the same common ancestor by carnal procreation." For all men descend from the same common ancestor, namely Adam, by carnal procreation. Therefore if the above definition of consanguinity is right, all men would be related by consanguinity: which is false.

❌ Objection 2 : Further, a tie is only between things in accord with one another, since a tie unites. Now there is not greater accordance between persons descended from a common ancestor than there is between other men, since they accord in species but differ in number, just as other men do. Therefore consanguinity is not a tie.

❌ Objection 3 : Further, carnal procreation, according to the Philosopher (De Gener. Anim. ii, 19), is effected from the surplus food [*Cf. FP, Question [119], Article [2]]. Now this surplus has more in common with that which is eaten, since it agrees with it in substance, than with him who eats. Since then no tie of consanguinity arises between the person born of semen and that which he eats, neither will there be any tie of kindred between him and the person of whom he is born by carnal procreation.

❌ Objection 4 : Further, Laban said to Jacob (Gn. 29:14): "Thou art my bone and my flesh," on account of the relationship between them. Therefore such a kinship should be called flesh-relationship rather than blood-relationship [consanguinitas].

❌ Objection 5 : Further, carnal procreation is common to men and animals. But no tie of consanguinity is contracted among animals from carnal procreation. Therefore neither is there among men.