 To play its appointed role, a criterion of ontological commitment should be ontologically neutral: it lets the theory speak for itself, as it were, without imposing ontological assumptions from the outside. Quinean criteria, however, by focusing only on the values of the (individual) variables, have been accused of being ontologically biased against realism about properties or universals because they fail to attach ontological significance to the predicate.[22] Consider ‘∃x Swims(x)’. According to Quinean criteria, this sentence is committed to entities that swim, but not to a property of swimming; for no property of swimming need be among the values of the bound variables in order for the sentence to be true. One way to ensure ontological neutrality is to switch to an entailment criterion. An entailment criterion—such as the modal entailment criterion in §1.5—avoids bias by allowing any component of a sentence to contribute to its ontological commitments, not just the (first-order) quantifiers and bound variables. If universals must exist in order for a theory to be true, then the theory is ontologically committed to universals; if not, not. And the same goes for particulars, or any other ontological category. This neutrality, however, comes at a price. The ontological commitments of a theory—indeed, of a simple subject-predicate sentence—cannot be determined prior to resolving the debate between nominalists and realists. Ontological commitments will not be transparent. Even a professed nominalist may in fact be committed to universals, willy-nilly. (For more on entailment accounts, see §2.)