 In any case, the changes recommended by free logicians would certainly undermine W. V. O. Quine’s (1953a) popular criterion for ontological commitment. Quine says that we can read off our ontology from the existentially quantified statements constituting our well-accepted theories. For instance, if evolutionary theory says that there are some species that evolved from other species, and if we have no way to paraphrase away this claim, then biologists are committed to the existence of species. Since philosophers cannot improve on the credentials of a scientific commitment, metaphysicians would also be obliged to accept species.