Note that, unlike the criteria for ontological commitment considered heretofore, this is intended only as a sufficient condition for ontological commitment. For one thing, just as Frege took singular terms to be a vehicle for commitment to objects, he took incomplete expressions to be a vehicle of commitment to concepts and (more generally) functions. Unlike Quine, Frege treated all meaningful expressions on a par with respect to ontological commitment. But even if we restrict our attention to ontological commitment to objects, there is no reason to think that Frege's criterion is necessary as well as sufficient. Frege could well have allowed existentially quantified sentences to be ontologically committed to objects, whether or not they were equivalent to disjunctions of sentences containing singular terms.