Reply Obj. 2: To state that which concerns oneself, in so far as it is a statement of what is true, is good generically. Yet this does not suffice for it to be an act of virtue, since it is requisite for that purpose that it should also be clothed with the due circumstances, and if these be not observed, the act will be sinful. Accordingly it is sinful to praise oneself without due cause even for that which is true: and it is also sinful to publish one's sin, by praising oneself on that account, or in any way proclaiming it uselessly.
Reply Obj. 3: A person who says what is true, utters certain signs which are in conformity with things; and such signs are either words, or external actions, or any external thing. Now such kinds of things are the subject-matter of the moral virtues alone, for the latter are concerned with the use of the external members, in so far as this use is put into effect at the command of the will. Wherefore truth is neither a theological, nor an intellectual, but a moral virtue. And it is a mean between excess and deficiency in two ways. First, on the part of the object, secondly, on the part of the act. On the part of the object, because the true essentially denotes a kind of equality, and equal is a mean between more and less. Hence for the very reason that a man says what is true about himself, he observes the mean between one that says more than the truth about himself, and one that says less than the truth. On the part of the act, to observe the mean is to tell the truth, when one ought, and as one ought. Excess consists in making known one's own affairs out of season, and deficiency in hiding them when one ought to make them known. _______________________
SECOND ARTICLE [II-II, Q. 109, Art. 2]
Whether Truth Is a Special Virtue?
Objection 1: It seems that truth is not a special virtue. For the true and the good are convertible. Now goodness is not a special virtue, in fact every virtue is goodness, because "it makes its possessor good." Therefore truth is not a special virtue.
Obj. 2: Further, to make known what belongs to oneself is an act of truth as we understand it here. But this belongs to every virtue, since every virtuous habit is made known by its own act. Therefore truth is not a special virtue.
Obj. 3: Further, the truth of life is the truth whereby one lives aright, and of which it is written (Isa. 38:3): "I beseech Thee . . . remember how I have walked before Thee in truth, and with a perfect heart." Now one lives aright by any virtue, as follows from the definition of virtue given above (I-II, Q. 55, A. 4). Therefore truth is not a special virtue.
Obj. 4: Further, truth seems to be the same as simplicity, since hypocrisy is opposed to both. But simplicity is not a special virtue, since it rectifies the intention, and that is required in every virtue. Therefore neither is truth a special virtue.
On the contrary, It is numbered together with other virtues (Ethic. ii, 7).
I answer that, The nature of human virtue consists in making a man's deed good. Consequently whenever we find a special aspect of goodness in human acts, it is necessary that man be disposed thereto by a special virtue. And since according to Augustine (De Nat. Boni iii) good consists in order, it follows that a special aspect of good will be found where there is a special order. Now there is a special order whereby our externals, whether words or deeds, are duly ordered in relation to some thing, as sign to thing signified: and thereto man is perfected by the virtue of truth. Wherefore it is evident that truth is a special virtue.