Chapter 7: Augustine traced original sin to inherited lust, not imputation

Do you want to know how we sinned through one will? From the will, he says, there is sin. Perhaps he seeks original sin too. I answer: original sin altogether, because this too was sown from the first man's will so that it might be in him and pass into all. Did he think with the learned man that it passes by imputation, and that its sole cause is God's will? Plainly the contrary; he contends it should be ascribed neither to God nor to human nature as from God, but to concupiscence or lust which passes from parent to children through seed. He does not want the vice to descend immediately from Adam by imputation, but mediately, and to be carried into the offspring from each nearest parent's vice by carnal generation. And when he asks how what is remitted in the parent is drawn into the offspring, he says it happens in wondrous ways, yet happens—and illustrates with the olive from which a wild olive is born. Had he sensed with the learned man, he would not have fled to nature, carnal generation, nearest parents' vice, or the wild-olive example, but to God's will, which was pleased immediately to impute Adam's actual sin to all his posterity and, to punish that imputed sin and satisfy justice, to inflict that original vice on them all. For otherwise, the learned man cries in many places—and namely cap. 11 §8, above at p. 125—no account of the matter can be given.