Quine's statement of his criterion (quoted above) appears to be modal. It asks: what entities must be taken to be values of the bound variables in order for the sentences of the theory to be true? But given Quine's general hostility to modality (e.g., in Quine 1953: 139–159), it is all but certain that he thought the ‘must’ was eliminable. Moreover, Quine explicitly claimed that his account of ontological commitment was within the theory of reference, not the theory of meaning (Quine 1953: 130–131). This suggests that Quine had in mind a purely extensional criterion, and an extensional individuation of kinds. Indeed, Quine provides an extensional criterion for a special case: the ontological commitments of an existential sentence.[5] He writes: