what was sought,” the slightest consideration has shown that not a single argument among them establishes the possibility of such a thing existing, whether in the mind or in external reality. I mean that he has established neither that reason knows that such a thing can be affirmed nor that it does not know it to be impossible. This would be so even if we held no belief ruling out its possibility through necessary knowledge or reasoning. How much more so, then, when its impossibility is known by necessity!

As previously explained, when something is held to be impossible on the basis of necessary knowledge, and someone wishes to show that neither necessary knowledge nor reasoning rules it out, but that it is mentally possible, he must demonstrate that what is known to be impossible through necessary knowledge or reasoning is not the same as that whose impossibility is unknown to the mind. Only then can mental possibility remain. Yet mental possibility does not entail possibility in external reality, as explained earlier.