 A third job for a criterion of transworld identity might be this: in order to understand the claim that there is some possible world in which George Eliot is a scientist, perhaps we must be able to give an informative answer to the question ‘What would it take for a scientist in another possible world to be identical with Eliot?’ Again, however, it can be argued that this demand is illegitimate, at least if what is demanded is that one be able to specify a set of properties whose possession, in another possible world, by an individual in that world, is non-trivially necessary and sufficient for being George Eliot (cf. Plantinga 1973; Plantinga 1974, 94–97; van Inwagen 1985).