Nineteenth aspect:
It includes the answer to the objection we mentioned earlier—that two mutually contradictory statements do not, by their very opposition, identify which one is truthful (1). Our reply is this (2): There is no doubt that their assertion, “Knowledge is incompatible with inward falsehood,” is correct, whereas their other claim—that knowledge may coexist with such inward falsehood, even if knowledge does not necessarily entail an inwardly truthful report—is erroneous. A person senses this within himself and knows it with certainty: whatever (3) he knows (4) cannot possibly be accompanied by an inward assertion that negates that knowledge. Were he commanded to do so, he would in effect be ordered to combine two opposites. Hence people have never differed over the impossibility of obligating someone to believe the contrary of what he knows. If, however, the existence of an inward report contrary to knowledge were possible, it would also be possible to demand it of a person, for one can be asked to perform anything that lies within his capacity (5), whether or not such a demand is deemed permissible under the Sacred Law—just as requesting an outward lie is conceivable and even legislating it is conceivable (6). As for demanding an inward lie that contradicts knowledge, this is something