16 R. Attend rather; for never can I be persuaded, that we have implored the Divine aid in vain. For I see that, having tried all things as far as we could, we found nothing to remain, which could rightly be called false, except what either feigns itself to be what it is not, or, to include all, tends to be and is not. But that former kind of falsity is either fallacious or mendacious. For that is rightly called fallacious which has a certain appetite of deceiving; which cannot be understood as without a soul: but this results in part from reason, in part from nature; from reason, in rational creatures, as in men; from nature, in beasts, as in the fox.
But what I call mendacious, proceeds from those who utter falsehood. Who in this point differ from the fallacious, that all the fallacious seek to mislead; but not every one who utters falsehood, wishes to mislead; for both mimes and comedies and many poems are full of falsehoods, rather with the purpose of delighting than of misleading, and almost all those who jest utter falsehood. But he is rightly called fallacious, whose purpose is, that somebody should be deceived. But those who do not aim to deceive, but nevertheless feign somewhat, are mendacious only, or if not even this, no one at least doubts that they are to be called pleasant falsifiers: unless you have something to object.
Source: Soliloquies (New Advent)