Reply Obj. 1: The true and the good are convertible as to subject, since every true thing is good, and every good thing is true. But considered logically, they exceed one another, even as the intellect and will exceed one another. For the intellect understands the will and many things besides, and the will desires things pertaining to the intellect, and many others. Wherefore the true considered in its proper aspect as a perfection of the intellect is a particular good, since it is something appetible: and in like manner the good considered in its proper aspect as the end of the appetite is something true, since it is something intelligible. Therefore since virtue includes the aspect of goodness, it is possible for truth to be a special virtue, just as the true is a special good; yet it is not possible for goodness to be a special virtue, since rather, considered logically, it is the genus of virtue.
Reply Obj. 2: The habits of virtue and vice take their species from what is directly intended, and not from that which is accidental and beside the intention. Now that a man states that which concerns himself, belongs to the virtue of truth, as something directly intended: although it may belong to other virtues consequently and beside his principal intention. For the brave man intends to act bravely: and that he shows his fortitude by acting bravely is a consequence beside his principal intention.
Reply Obj. 3: The truth of life is the truth whereby a thing is true, not whereby a person says what is true. Life like anything else is said to be true, from the fact that it attains its rule and measure, namely, the divine law; since rectitude of life depends on conformity to that law. This truth or rectitude is common to every virtue.
Reply Obj. 4: Simplicity is so called from its opposition to duplicity, whereby, to wit, a man shows one thing outwardly while having another in his heart: so that simplicity pertains to this virtue. And it rectifies the intention, not indeed directly (since this belongs to every virtue), but by excluding duplicity, whereby a man pretends one thing and intends another. _______________________
THIRD ARTICLE [II-II, Q. 109, Art. 3]
Whether Truth Is a Part of Justice?
Objection 1: It seems that truth is not a part of justice. For it seems proper to justice to give another man his due. But, by telling the truth, one does not seem to give another man his due, as is the case in all the foregoing parts of justice. Therefore truth is not a part of justice.
Obj. 2: Further, truth pertains to the intellect: whereas justice is in the will, as stated above (Q. 58, A. 4). Therefore truth is not a part of justice.
Obj. 3: Further, according to Jerome truth is threefold, namely, "truth of life," "truth of justice," and "truth of doctrine." But none of these is a part of justice. For truth of life comprises all virtues, as stated above (A. 2, ad 3): truth of justice is the same as justice, so that it is not one of its parts; and truth of doctrine belongs rather to the intellectual virtues. Therefore truth is nowise a part of justice.
On the contrary, Tully (De Invent. Rhet. ii) reckons truth among the parts of justice.