On the Virginal Conception, and On Original Sin: Chapter 10
BASIC WRITINGS
woman from Adam, in whom he had created the seed of all human beings; and by that other woman made from Adam, God's purpose would have been fulfilled. For these same reasons, I will signify them both by the name 'Adam', except when it is necessary to distinguish the two of them.
Chapter 10 Why those who were not Adam's accomplices are burdened by his sin It is through creation that all the offspring of Adam are human beings,through propagation that they are Adam, and through the individuation by which they are distinguished from others that they are persons. For it is not from Adam, but through Adam, that they possess their being human. Just as Adam did not make himself a human being, he also did not make the reproductive nature that he possessed; rather God, who created Adam a human being, made this nature in him so that human beings would be propagated from him. Now there is no doubt about the basis on which all his offspring incur the debt about which we are speaking. It is not because they are human beings or because they are persons.After all, if it is because they are human beings or persons that they are all liable for this debt, then Adam would necessarily have been constrained by this debt before he sinned, since he too was a human being and a person—and that is altogether ridiculous. The only remaining possibility, then, is that all his offspring are debtors for no other reason than that they are Adam: not, however, because they are Adam without qualification, but because they are Adam the sinner. Otherwise it would follow that even if Adam had never sinned, those who were propagated from him would nevertheless have been born owing this debt—an impious conclusion.
It is appropriate to repeat here what I said earlier28 about why they are all burdened by the sin or debt of Adam because they are propagated from him, even though they were not accomplices in his sin.When God made Adam, he made a reproductive nature in him, and God placed this nature under his control so that he would use it in accordance with his own will, so long as he should will to be subject to God. For Adam would not use this nature in accordance with bestial and irrational passion, but in accordance with a human and rational will.After all, it is proper to beasts to will nothing in conjunction with reason, whereas it is proper to human beings to will nothing apart from reason. They are always under the obligation to do this, since Adam received this power and was able to preserve it always. God also gave him this gift of grace: so long as he did not sin, those whom he generated by the workings of nature and will would be just, as soon as they came to possess a rational soul—
28 See Chapter 2.