itself, cannot occur in anything else; otherwise, that thing would be identical with something other than itself, which is invalid according to the self-evident principles of reason. It is thus established that the individuation of each thing, insofar as it is itself, cannot occur in anything else. We therefore know that the absence of a counterpart or equal does not require us to affirm the thing’s nonexistence.”

The response is: This argument is even more unsound than the others. It too is among his fallacies, for he has offered nothing in it that establishes his claim, for several reasons.

First, affirming a thing’s counterpart, likeness, or equal entails that one is not identical with the other. If they were identical, one would not be the other’s likeness or counterpart; rather, it would be that very thing. Since affirming a counterpart itself entails distinct individual identities, the existence of a counterpart entails that neither can be identical with the other. Yet the existence of what is entailed does not imply the nonexistence of that which entails it. Thus, the fact that a thing’s identity cannot belong to something else does not imply the nonexistence of a counterpart, any more than it implies its existence. Since it entails neither the existence nor the nonexistence of a counterpart, it amounts only to an absence of evidence that a counterpart must exist. But absence of evidence is not evidence of absence. It is therefore clear that what he has stated does not rule out the necessity of a counterpart, just as