tellectual virtue is the true; in the case
of contemplative virtue, it is the true taken absolutely (Ethic. vi,
2); in the case of practical virtue, it is the true in conformity
with a right appetite.

Now truth apprehended by our intellect, if we consider it absolutely,
is measured by things; since things are the measure of our intellect,
as stated in _Metaph._ x, text. 5; because there is truth in what we
think or say, according as the thing is so or not. Accordingly the
good of speculative intellectual virtue consists in a certain mean,
by way of conformity with things themselves, in so far as the
intellect expresses them as being what they are, or as not being what
they are not: and it is in this that the nature of truth consists.
There will be excess if something false is affirmed, as though
something were, which in reality it is not: and there will be
deficiency if something is falsely denied, and declared not to be,
whereas in reality it is.

The truth of practical intellectual virtue, if we consider it in
relation to things, is by way of that which is measured; so that both
in practical and in speculative intellectual virtues, the mean
consists in conformity with things. But if we consider it in relation
to the appetite, it has the character of a rule and measure.
Consequently the rectitude of reason is the mean of moral virtue, and
also the mean of prudence--of prudence as ruling and measuring, of
moral virtue, as ruled and measured by that mean. In like manner the
difference between excess and deficiency is to be applied in both
cases.

Reply Obj. 1: Intellectual virtues also have their measure, as
stated, and they observe the mean according as they conform to that
measure.

Reply Obj. 2: There is no need for an indefinite series of virtues:
because the measure and rule of intellectual virtue is not another
kind of virtue, but things themselves.

Reply Obj. 3: The things themselves that are contrary have no
contrariety in the mind, because one is the reason for knowing the
other: nevertheless there is in the intellect contrariety of
affirmation and negation, which are contraries, as stated at the end
of _Peri Hermen[e]ias._ For though "to be" and "not to be" are not in
contrary, but in contradictory opposition to one another, so long as
we consider their signification in things themselves, for on the one
hand we have "being" and on the other we have simply "non-being"; yet
if we refer them to the act o