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.

Obj. 2: Further, the reason is a power of apprehension. But moral

virtue does not observe a mean between apprehensions, but rather a

mean between operations or passions. Therefore the mean of moral

virtue is not the rational, but the real mean.

Obj. 3: Further, a mean that is observed according to arithmetical or

geometrical proportion is a real mean. Now such is the mean of

justice, as stated in _Ethic._ v, 3. Therefore the mean of moral

virtue is not the rational, but the real mean.

_On the contrary,_ The Philosopher says (Ethic. ii, 6) that "moral

virtue observes the mean fixed, in our regard, by reason."

_I answer that,_ The rational mean can be understood in two ways.

First, according as the mean is observed in the act itself of reason,

as though the very act of reason were made to observe the mean: in

this sense, since moral virtue perfects not the act of reason, but

the act of the appetitive power, the mean of moral virtue is not the

rational mean. Secondly, the mean of reason may be considered as that

which the reason puts into some particular matter. In this sense

every mean of moral virtue is a rational mean, since, as above stated

(A. 1), moral virtue is said to observe the mean, through conformity

with right reason.

But it happens sometimes that the rational mean is also the real

mean: in which case the mean of moral virtue is the real mean, for

instance, in justice. On the other hand, sometimes the rational mean

is not the real mean, but is considered in relation to us: and such

is the mean in all the other moral virtues. The reason for this is

that justice is about operations, which deal with external things,

wherein the right has to be established simply and absolutely, as

stated above (Q. 60, A. 2): wherefore the rational mean in justice is

the same as the real mean, in so far, to wit as justice gives to each

one his due, neither more nor less. But the other moral virtues deal

with interior passions wherein the right cannot be established in the

same way, since men are variously situated in relation to their

passions; hence the rectitude of reason has to be established in the

passions, with due regard to us, who are moved in respect of the

passions.

This suffices for the Replies to the Objections. For the first two

arguments take the rational mean as being in the very act of reason,

while the third argues from the mean of justice.

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Summa Theologica, Part I-II (Pars Prima Secundae) From the Complete American Edition · 第 413 / 746 题