Reply Obj. 1:  Moral virtue derives goodness from the rule of reason, while its matter consists in passions or operations.  If therefore we compare moral virtue to reason, then, if we look at that which it has of reason, it holds the position of one extreme, viz. conformity; while excess and defect take the position of the other extreme, viz. deformity.  But if we consider moral virtue in respect of its matter, then it holds the position of mean, in so far as it makes the passion conform to the rule of reason.  Hence the Philosopher says (Ethic. ii, 6) that “virtue, as to its essence, is a mean state,” in so far as the rule of virtue is imposed on its proper matter:  “but it is an extreme in reference to the ‘best’ and the ’excellent, ’” viz. as to its conformity with reason.

Reply Obj. 2:  In actions and passions the mean and the extremes depend on various circumstances:  hence nothing hinders something from being extreme in a particular virtue as to one circumstance, while the same thing is a mean in respect of other circumstances, through being in conformity with reason.  This is the case with magnanimity and magnificence.  For if we look at the absolute quantity of the respective objects of these virtues, we shall call it an extreme and a maximum:  but if we consider the quantity in relation to other circumstances, then it has the character of a mean:  since these virtues tend to this maximum in accordance with the rule of reason, i.e. where it is right, when it is right, and for an end that is right.  There will be excess, if one tends to this maximum when it is not right, or where it is not right, or for an undue end; and there will be deficiency if one fails to tend thereto where one ought, and when one ought.  This agrees with the saying of the Philosopher (Ethic. iv, 3) that the “magnanimous man observes the extreme in quantity, but the mean in the right mode of his action.”

Reply Obj. 3:  The same is to be said of virginity and poverty as of magnanimity.  For virginity abstains from all sexual matters, and poverty from all wealth, for a right end, and in a right manner, i.e. according to God’s word, and for the sake of eternal life.  But if this be done in an undue manner, i.e. out of unlawful superstition, or again for vainglory, it will be in excess.  And if it be not done when it ought to be done, or as it ought to be done, it is a vice by deficiency:  for instance, in those who break their vows of virginity or poverty. ________________________

SECOND ARTICLE [I-II, Q. 64, Art. 2]

Whether the Mean of Moral Virtue Is the Real Mean, or the Rational
Mean?

Objection 1:  It would seem that the mean of moral virtue is not the rational mean, but the real mean.  For the good of moral virtue consists in its observing the mean.  Now, good, as stated in Metaph. ii, text. 8, is in things themselves.  Therefore the mean of moral virtue is a real mean.