Abstract

Frege's account of opacity is based on two attractive ideas: every meaningful expression has a sense (Sinn) that determines the expression's semantic value (Bedeutung); and the semantic value of a‘that’‐clause is the thought expressed by its embedded sentence. Considerations of compositionality led Frege to a more problematic view: inside ‘that’‐clauses, an expression does not have its customary Bedeutung. But contrary to initial appearances, compositionality does not entail a familiar substitutivity principle. And Fregeans can exploit this point in a way that lets them reject Bedeutung‐shifting.