 In sum, Church’s argument for the existence of propositions is as follows. (1) Actual thought or sentence tokens, as well as possible sentences, are insufficient for semantics to be a true and humanly understandable theory. Rather, (2) propositions are also needed. Further, by Church’s criterion of ontological commitment, (3) if entities of kind \(K\) are entailed by a true theory, then there exist entities of kind \(K\). So, (4) there exist propositions. Church (1952, 1958a) chides Ayer and Ryle for not taking this last step, that is for inadvertently committing themselves to propositions while talking about propositional attitudes but denying their existence while talking explicitly about propositions as theoretical commitments.