On the contrary, Original justice has a prior relation to the will, because it is “rectitude of the will,” as Anselm states (De Concep.  Virg. iii).  Therefore original sin, which is opposed to it, also has a prior relation to the will.

I answer that, Two things must be considered in the infection of original sin.  First, its inherence to its subject; and in this respect it regards first the essence of the soul, as stated above (A. 2).  In the second place we must consider its inclination to act; and in this way it regards the powers of the soul.  It must therefore regard first of all that power in which is seated the first inclination to commit a sin, and this is the will, as stated above (Q. 74, AA. 1, 2).  Therefore original sin regards first of all the will.

Reply Obj. 1:  Original sin, in man, is not caused by the generative power of the child, but by the act of the parental generative power.  Consequently, it does not follow that the child’s generative power is the subject of original sin.

Reply Obj. 2:  Original sin spreads in two ways; from the flesh to the soul, and from the essence of the soul to the powers.  The former follows the order of generation, the latter follows the order of perfection.  Therefore, although the other, viz. the sensitive powers, are more akin to the flesh, yet, since the will, being the higher power, is more akin to the essence of the soul, the infection of original sin reaches it first.

Reply Obj. 3:  The intellect precedes the will, in one way, by proposing its object to it.  In another way, the will precedes the intellect, in the order of motion to act, which motion pertains to sin. ________________________

FOURTH ARTICLE [I-II, Q. 83, Art. 4]

Whether the Aforesaid Powers Are More Infected Than the Others?

Objection 1:  It would seem that the aforesaid powers are not more infected than the others.  For the infection of original sin seems to pertain more to that part of the soul which can be first the subject of sin.  Now this is the rational part, and chiefly the will.  Therefore that power is most infected by original sin.

Obj. 2:  Further, no power of the soul is infected by guilt, except in so far as it can obey reason.  Now the generative power cannot obey reason, as stated in Ethic. i, 13.  Therefore the generative power is not the most infected by original sin.

Obj. 3:  Further, of all the senses the sight is the most spiritual and the nearest to reason, in so far “as it shows us how a number of things differ” (Metaph. i).  But the infection of guilt is first of all in the reason.  Therefore the sight is more infected than touch.

On the contrary, Augustine says (De Civ.  Dei xiv, 16, seqq., 24) that the infection of original sin is most apparent in the movements of the members of generation, which are not subject to reason.  Now those members serve the generative power in the mingling of sexes, wherein there is the delectation of touch, which is the most powerful incentive to concupiscence.  Therefore the infection of original sin regards these three chiefly, viz. the generative power, the concupiscible faculty and the sense of touch.