that would bar him from acknowledging them and require him to deny them, since nothing contrary to reason can be affirmed—unless “contrary to reason” is understood to mean “having no parallel.” In that case, however, there is no difference between contradicting reason and contradicting sense perception: neither precludes the existence of something contrary to it. His purpose can only be achieved by distinguishing between the two and establishing something that sense perception deems impossible but reason does not, as we explained earlier.

The crux of the matter may be stated as follows: If you cannot rationally conceive of anything coming into being except within time, yet affirm something you cannot thus conceive, does this warrant your affirming what your reason knows to be impossible? If it warrants affirming what reason knows to be impossible, he can no longer rule anything out as impossible on rational grounds. Rather, things whose impossibility is known by reason, whether self-evidently or through inference, could exist. No rational person would maintain this.

If he says, “This does not warrant affirming what reason knows to be impossible,” then it does not help you on the point at issue. For your opponent claims to know, through his innate disposition, that what you have affirmed is impossible. This does not show that a judgment of impossibility known through reason can be overturned, as you have conceded; nor does it show this for a judgment based on sense perception, since you did not mention it.