of a sin is not increased by the greatness of
its cause.

_On the contrary,_ If the cause be increased, the effect is
increased. Therefore the greater the cause of sin, the more grievous
the sin.

_I answer that,_ In the genus of sin, as in every other genus, two
causes may be observed. The first is the direct and proper cause of
sin, and is the will to sin: for it is compared to the sinful act, as
a tree to its fruit, as a gloss observes on Matt. 7:18, "A good tree
cannot bring forth evil fruit": and the greater this cause is, the
more grievous will the sin be, since the greater the will to sin, the
more grievously does man sin.

The other causes of sin are extrinsic and remote, as it were, being
those whereby the will is inclined to sin. Among these causes we must
make a distinction; for some of them induce the will to sin in accord
with the very nature of the will: such is the end, which is the
proper object of the will; and by a such like cause sin is made more
grievous, because a man sins more grievously if his will is induced
to sin by the intention of a more evil end. Other causes incline the
will to sin, against the nature and order of the will, whose natural
inclination is to be moved freely of itself in accord with the
judgment of reason. Wherefore those causes which weaken the judgment
of reason (e.g. ignorance), or which weaken the free movement of the
will, (e.g. weakness, violence, fear, or the like), diminish the
gravity of sin, even as they diminish its voluntariness; and so much
so, that if the act be altogether involuntary, it is no longer sinful.

Reply Obj. 1: This argument considers the extrinsic moving cause,
which diminishes voluntariness. The increase of such a cause
diminishes the sin, as stated.

Reply Obj. 2: If concupiscence be understood to include the movement
of the will, then, where there is greater concupiscence, there is a
greater sin. But if by concupiscence we understand a passion, which
is a movement of the concupiscible power, then a greater
concupiscence, forestalling the judgment of reason and the movement
of the will, diminishes the sin, because the man who sins, being
stimulated by a greater concupiscence, falls through a more grievous
temptation, wherefore he is less to be blamed. On the other hand, if
concupiscence be taken in this sense follows the judgment of reason,
and the movement of the will, then the greater concupiscence, the
graver the sin: because sometimes t