 Frege's case for the sense-reference distinction is also a case that singular propositions are not the semantic contents of natural language sentences and are not the objects of the propositional attitudes. Singular propositions are too coarse-grained to account for what a competent speaker understands in virtue of grasping the meaning of a sentence. But the content of a sentence is, intuitively, what an agent grasps when she understands a sentence and what she believes when she accepts it. Frege concluded that singular propositions are ill-suited for the purposes of semantics and psychology, as they lead to violations of Accept and Attitude. (For further discussion, see the entry  Frege.) 