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 of the mind, there is something positive in both cases.  Hence “to be” and “not to be” are contradictory:  but the opinion stating that “good is good” is contrary to the opinion stating that “good is not good”:  and between two such contraries intellectual virtue observes the mean. ________________________

FOURTH ARTICLE [I-II, Q. 64, Art. 4]

Whether the Theological Virtues Observe the Mean?

Objection 1:  It would seem that theological virtue observes the mean.  For the good of other virtues consists in their observing the mean.  Now the theological virtues surpass the others in goodness.  Therefore much more does theological virtue observe the mean.

Obj. 2:  Further, the mean of moral virtue depends on the appetite being ruled by reason; while the mean of intellectual virtue consists in the intellect being measured by things.  Now theological virtue perfects both intellect and appetite, as stated above (Q. 62, A. 3).  Therefore theological virtue also observes the mean.

Obj. 3:  Further, hope, which is a theological virtue, is a mean between despair and presumption.  Likewise faith holds a middle course between contrary heresies, as Boethius states (De Duab.  Natur. vii):  thus, by confessing one Person and two natures in Christ, we observe the mean between the heresy of Nestorius, who maintained the existence of two persons and two natures, and the heresy of Eutyches, who held to one person and one nature.  Therefore theological virtue observes the mean.

On the contrary, Wherever virtue observes the mean it is possible to sin by excess as well as by deficiency.  But there is no sinning by excess against God, Who is the object of theological virtue:  for it is written (Ecclus. 43:33):  “Blessing the Lord, exalt Him as much as you can:  for He is above all praise.”  Therefore theological virtue does not observe the mean.

I answer that, As stated above (A. 1), the mean of virtue depends on conformity with virtue’s rule or measure, in so far as one may exceed or fall short of that rule.  Now the measure of theological virtue may be twofold.  One is taken from the very nature of virtue, and thus the measure and rule of theological virtue is God Himself:  because our faith is ruled according to Divine truth; charity, according to His goodness; hope, according to the immensity of His omnipotence and loving kindness.  This measure surpasses all human power:  so that never can we love God as much as He ought to be loved, nor believe and hope in Him as much as we should.  Much less therefore can there be excess in such things.  Accordingly the good of such virtues does not consist in a mean, but increases the more we approach to the summit.