 A natural analysis of such sentences is that they express a relation between Seneca or Columbus and the propositions that man is a rational animal or that the world is round, where such propositions are objective abstract entities that are the ultimate vehicles of truth and meaning. But there has been—and no doubt always will be—skepticism about the existence of such entities and this has motivated the view that sentences such as (1) and (2) express relations between agents and sentence types or even particular inscriptions (or other tokens) of sentences of a particular language, where sentences are assumed to be more concrete than propositions. While this assumption of concreteness seems highly questionable in the case of sentence types, Carnap and others nevertheless vigorously pursued the project of analyzing (1) and (2) in terms that relate agents to such types. (The theory that saying and believing are relations to particular physical tokens is obviously implausible. Contrary to what it predicts, the destruction of such tokens would not have voided Seneca’s belief.) In response, Church deployed his translation argument (CTA) that if we limit our ontology to sentence types, then our semantic theory will not be able to provide a true analysis of sentences like (1) and (2). (This is a crucial part of Church’s broader argument that no philosophical theory that is both true and humanly understandable can do without propositions. We return to the rest of the argument in  §6.3.)