The basic linguistic phenomenon of presupposition is commonplace and intuitive, little different from the relation described by the word presuppose in its everyday usage. In ordinary language, when we say that someone presupposes something, we mean that they assume it, or take it for granted. The term is used in the same way when we talk of a speaker presupposing something, although typically we are interested in those assumptions which are revealed by what the speaker says. To begin with the most venerable case of presupposing, first discussed by Frege 1892, when a speaker makes an assertion, “there is always an obvious presupposition that the simple or compound proper names used have reference.” So a speaker who says: