II. To the Initial Arguments for the First Side

22. To the arguments.

To the first [n.4] I say, as was said above in d.17 [n.19], that something is said to belong to the law of nature in two ways:

In the first way, certainly, that what is a practical truth simply is known simply by the light of nature; and there the highest rank is held by a practical principle known from the terms; the second rank is held by a conclusion demonstratively proven by such principles.

But belonging secondarily to the law of nature is what is regularly consonant with the law of nature stated in the first way.

23. No dispensation happens against the first, and therefore the opposite of it seems to be always a mortal sin.

Dispensation from the second happens in a case where the opposite would seem to be commonly consonant with the law of nature, and precisely in this second way is monogamy of the law of nature and bigamy against it. And in this way do I concede the assertions in Genesis 2 and the gloss on Genesis 4 [n.4].

24. Nor yet does it follow from this that in some case the opposite could not be licit; indeed, it is necessary even as to the exchanging of justice on the side of the parties exchanging and of the things exchanged - when by reason of necessity right reason dictates the exchange must in some way be done, and when there is a divine precept there.

25. I say that the authority “they will be two in one flesh” [n.4] must be taken to mean that they will be ‘one flesh’ by reason of the offspring that is generated from both parents; and so it is not repugnant to the first institution of matrimony to have several wives. Or it can be said etc. [as in n.24].

26. About Lamech however [n.4], it can absolutely be conceded that he sinned mortally, because against a law of nature even if taken in the second way; he sinned, I say, by making a contract with several women not in a case where right reason would dictate that the law was to be revoked, nor where the superior gave dispensation; rather the contract was opposed to both.

27. To the second argument [n.5] I say that, on the part of the contract, justice between the exchanging parties was never to exchange in a way that the more principal end happen less and the less principal end happen more, because the more principal end is more to be willed; but biviry would be more for the less principal end and much less for the more principal end; because the same woman cannot within the same time be impregnated by several men.