1. What Original Sin is

50. As to the first article Anselm says in the cited book [n.48] ch.27, “This sin, which I call ‘original’, I cannot understand to be anything other in infants than the very being stripped naked of an owed justice, a nakedness brought about by Adam’s disobedience, through which all are ‘sons of wrath’ [Ephesians 2.3].”

51. This account of original sin is proved by the fact that [Anselm ibid. ch.3] sin is formally injustice, and that such a sin is such an injustice [cf. below dd.34-37 n.51]; now injustice is nothing but lack of owed justice, according to Anselm ibid. ch.5 (and On the Fall of the Devil ch.16], when he says that original sin - which is lack of original justice - is nothing but lack of owed justice [also Giles of Rome, Roger Marston, Aquinas].

52. And if it is objected that other saints seem to say that concupiscence is original sin, I reply:

Concupiscence can be taken for an act or a habit or a proneness in the sensitive appetite, and none of these is formally sin, because there is no sin in the sensitive part according to Anselm ibid. chs.3-4. Or it can be taken for a proneness in the rational part or appetite (or the rational appetite) for coveting delights inordinately and immoderately, which rational appetite is of a nature to delight with the sensitive appetite to which it is joined; and in this way concupiscence is the material of original sin because, by the lack of original justice (which was as a bridle restraining it from immoderate delight), the rational appetite becomes, not positively but through privation, prone to coveting immoderately delightful things (as Anselm exemplifies, ch.5, about a ship with a broken rudder and about a horse with a broken bridle that falls off it); and from this follows, in the issue at hand, the inordinate motion that the bridle was restraining.

53. Hereby is the second question solved [nn.9, 49], where the question is asked what original sin is. For it is formally a lack of owed original justice - not owed, however, in just any way, but owed because received in the first parent and in him lost; and therefore Adam did not have original sin, because this debt was not passed on to him by any parent, but he received the justice in himself and by his act he lost it.