ABSTRACT. Sowa asserts that context and background knowledge are important, since most sentences cannot be understood in isolation. Carnap makes an analogous distinction between descriptive and pure syntax: descriptive syntax is an empirical investigation of the syntactical features of given languages; pure syntax deals with syntactical systems. Davidson maintains that to have a belief it is not enough to discriminate among aspects of the world, to behave in different ways in different circumstances. Chomsky says that the grammar as a whole can be regarded as a device for pairing phonetically represented signals with semantic representations.