 Like the impossibility of contingent identity, the impossibility of vague identity appears to be a straightforward consequence of the classical concept of identity (Evans 1978, see also Salmon 1982). For if a is only vaguely identical with b, something is true of it – that it is only vaguely identical with b – that is not true of b, so, by Leibniz’s Law, it is not identical with b at all. Of course, there are vague statements of identity – “Princeton is Princeton Borough” (Lewis 1988) – but the conclusion appears to follow that such vagueness is only possible when one or both of the terms flanking the sign of identity is an imprecise designator. Relatedly, it appears to follow that identity itself must be a determinate relation.