end. The "human reason" pronounces judgment concerning the character of the end, it is, therefore, the law for
action. Human acts, however, are meritorious in so far as they promote the purpose of God and his honor.
By repeating a good action man acquires a moral habit or a quality which enables him to do the good gladly and
easily. This is true, however, only of the intellectual and moral virtues, which Aquinas treats after the manner of
Aristotle; the theological virtues are imparted by God to man as a "disposition", from which the acts here
proceed, but while they strengthen, they do not form it. The "disposition" of evil is the opposite alternative. An
act becomes evil through deviation from the reason and the divine moral law. Therefore, sin involves two
factors: its substance or matter is lust; in form, however, it is deviation from the divine law.
Sin has its origin in the will, which decides, against the reason, for a "changeable good". Since, however, the
will also moves the other powers of man, sin has its seat in these too. By choosing such a lower good as end, the
will is misled by self-love, so that this works as cause in every sin. God is not the cause of sin, since, on the
contrary, he draws all things to himself. But from another side God is the cause of all things, so he is efficacious
also in sin as
but not as
. The devil is not directly the cause of sin, but he incites by working on the
imagination and the sensuous impulse of man, as men or things may also do.
. Adam's first sin passes upon himself and all the succeeding race; because he is the head of
the human race and "by virtue of procreation human nature is transmitted and along with nature its infection".
The powers of generation are, therefore, designated especially as "infected". The thought is involved here by the
fact that Aquinas, like the other scholastics, held to creationism, therefore taught that the souls are created by
God. Two things according to Aquinas constituted man's righteousness in paradise — the
the harmony of all man's powers before they were blighted by desire, and the possession of the
(the continuous indwelling power of good). Both are lost through original sin, which in form is the "loss
of original righteousness". The consequence of this loss is the disorder and maiming of man's nature, which
shows itself in "ignorance; malice, moral weakness, and especially in
, which is the material
principle of original sin". The course of thought here is as follows: when the first man transgressed the order of
his nature appointed by nature and grace, he, and with him the human race, lost this order. This negative state is