Reply Obj. 3:  As Augustine says (De Civ.  Dei xiv, 17, 20) it is in punishment of sin that the movement of these members does not obey reason:  in this sense, that the soul is punished for its rebellion against God, by the insubmission of that member whereby original sin is transmitted to posterity.

But because, as we shall state later on, the effect of the sin of our first parent was that his nature was left to itself, through the withdrawal of the supernatural gift which God had bestowed on man, we must consider the natural cause of this particular member’s insubmission to reason.  This is stated by Aristotle (De Causis Mot.  Animal.) who says that “the movements of the heart and of the organs of generation are involuntary,” and that the reason of this is as follows.  These members are stirred at the occasion of some apprehension; in so far as the intellect and imagination represent such things as arouse the passions of the soul, of which passions these movements are a consequence.  But they are not moved at the command of the reason or intellect, because these movements are conditioned by a certain natural change of heat and cold, which change is not subject to the command of reason.  This is the case with these two organs in particular, because each is as it were a separate animal being, in so far as it is a principle of life; and the principle is virtually the whole.  For the heart is the principle of the senses; and from the organ of generation proceeds the seminal virtue, which is virtually the entire animal.  Consequently they have their proper movements naturally:  because principles must needs be natural, as stated above (Reply Obj. 2). ________________________

QUESTION 18

OF THE GOOD AND EVIL OF HUMAN ACTS, IN GENERAL (In Eleven Articles)

We must now consider the good and evil of human acts.  First, how a human act is good or evil; secondly, what results from the good or evil of a human act, as merit or demerit, sin and guilt.

Under the first head there will be a threefold consideration:  the first will be of the good and evil of human acts, in general; the second, of the good and evil of internal acts; the third, of the good and evil of external acts.

Concerning the first there are eleven points of inquiry: 

(1) Whether every human action is good, or are there evil actions?

(2) Whether the good or evil of a human action is derived from its object?

(3) Whether it is derived from a circumstance?

(4) Whether it is derived from the end?

(5) Whether a human action is good or evil in its species?

(6) Whether an action has the species of good or evil from its end?

(7) Whether the species derived from the end is contained under the species derived from the object, as under its genus, or conversely?

(8) Whether any action is indifferent in its species?