Before addressing the objection from extrinsic properties, it is important to note an ambiguity in the informal expression of the quantifier account. When we ask, following Quine, “what entities must be values of the variables” in order for a theory T to be true, we might mean: what entities must be assigned to the variables of the sentences in T in order for T to be true. Or we might mean: what entities must be included in the domain of the interpretation of T in order for T to be true, whether or not those entities must be assigned to the variables of the sentences in T. When predicates of the theory express extrinsic properties, this difference matters. In this article, Quine's criterion—and quantifier criteria more generally—have always been understood in the first, stronger way. But those philosophers who take Quine's criterion to be compatible with an entailment approach to ontological commitment are best understood as interpreting him in the second, weaker way.