FP, Q, A] act at the command of reason. Therefore in these powers there can be virtue.
Objection 2: Further, as the rational appetite, which is the will, can be hindered or helped in its act, by the sensitive appetite, so also can the intellect or reason be hindered or helped by the powers mentioned above. As, therefore, there can be virtue in the interior powers of appetite, so also can there be virtue in the interior powers of apprehension.
Objection 3: Further, prudence is a virtue, of which Cicero (De Invent. Rhetor. ii) says that memory is a part. Therefore also in the power of memory there can be a virtue: and in like manner, in the other interior sensitive powers of apprehension.
On the contrary, All virtues are either intellectual or moral (Ethic. ii, 1). Now all the moral virtues are in the appetite; while the intellectual virtues are in the intellect or reason, as is clear from Ethic. vi, 1. Therefore there is no virtue in the interior sensitive powers of apprehension.
I answer that, In the interior sensitive powers of apprehension there are some habits. And this is made clear principally from what the Philosopher says (De Memoria ii), that "in remembering one thing after another, we become used to it; and use is a second nature." Now a habit of use is nothing else than a habit acquired by use, which is like unto nature. Wherefore Tully says of virtue in his Rhetoric that "it is a habit like a second nature in accord with reason." Yet, in man, that which he acquires by use, in his memory and other sensitive powers of apprehension, is not a habit properly so called, but something annexed to the habits of the intellective faculty, as we have said above (Q, A, ad 3).
Nevertheless even if there be habits in such powers, they cannot be virtues. For virtue is a perfect habit, by which it never happens that anything but good is done: and so virtue must needs be in that power which consummates the good act. But the knowledge of truth is not consummated in the sensitive powers of apprehension: for such powers prepare the way to the intellective knowledge. And therefore in these powers there are none of the virtues, by which we know truth: these are rather in the intellect or reason.
Reply to Objection 1: The sensitive appetite is related to the will, which is the rational appetite, through being moved by it. And therefore the act of the appetitive power is consummated in the sensitive appetite: and for this reason the sensitive appetite is the subject of virtue. Whereas the sensitive powers of apprehension are related to the intellect rather through moving it; for the reason that the phantasms are related to the intellective soul, as colors to sight (De Anima iii, text.18). And therefore the act of knowledge is terminated in the intellect; and for this reason the cognoscitive virtues are in the intellect itself, or the reason.
And thus is made clear the Reply to the Second Objection.
Reply to Objection 3: Memory is not a part of prudence, as species is of a genus, as though memory were a virtue properly so called: but one of the conditions required for prudence is a good memory; so that, in a fashion, it is after the manner of an integral part.