Article I: On the Virtue and Opposite Vices

1. Notions. The noble virtue of truth or veracity inclines to the right use of signs by which man communicates with others or has commerce. Through it there is effected "that one show himself exteriorly, by exterior signs, such as he is" (2, 2, q. 109, art. 1, c.). From that moral virtue, the truth itself which it procures is called moral truth. We can fall short of the true both by amplification, or by saying the greater, and by attenuation, or by saying the lesser. Therefore the formal object of the virtue, or the honesty of moral truth, is discerned to have been placed in the mean. Even on the part of its act, this virtue is in the mean; for if more principally we are commanded to manifest the soul in speaking, nevertheless we must open the mind in such a way that we do not derogate from the office of preserving secrecy.

Therefore properly and strictly the virtue of truth fosters the cult of taking care that words or equivalent signs are consonant with our mind. That unity of the exterior and interior man is seen to be honorable per se, and is shown to contribute to the good of human society. Moreover, the virtue of truth appears joined per se to justice; for it procures a certain equality, and makes our conversation with others right: therefore it contains respect of others. Its office can also, in certain cases, be commanded by commutative justice.

2. On sincerity. For the good of social living together, it also helps that man be not only true in his speech, but also sufficiently open, or that he not deny to others an opportune manifestation of himself. Sincerity regards this, which makes us inclined to a full, yet prudent manifestation of ourselves. It is in the middle between distrustful dissimulation and indiscreet revelation of one's own affairs.

3. The opposite vice by excess is indiscretion; by defect, lying. - Simulation is lying by deeds. - Hypocrisy denotes this particular simulation by which someone simulates himself as different from what he is; while dissimulation merely hides one's own person.