Veridicum laudare necesse est, vitam sustinere non est necesse

As for the external relationship of (un)truthfulness to valuation of human behaviour, first, the dominant role of human concern with (un)truthfulness is pointed out, and second, a claim is presented to the effect that one's infringing, in what one says, upon truthfulness brings about detrimental consequences for one's interlocutors' image of that most important part of reality which consists in knowledge of their communication partners, in particular, of their partners' readiness to act in this direction or another. These consequences appear to be by far more weighty from the axiological point of view than mere “matter-of-fact” misinformation which may result from untruthfulness, relative to propositions expressed in given utterances.