 Early advocates of RTM (e.g., Locke (1690/1975) and Hume (1739/1978)) called these more basic representations ideas, and often took them to be mental images. But modern versions of RTM assume that much thought is not grounded in mental images. The classic contemporary treatment maintains, instead, that the internal system of representation has a language-like syntax and a compositional semantics. According to this view, much of thought is grounded in word-like mental representations. This view is often referred to as the language of thought hypothesis (Fodor 1975). However, the analogy with language isn’t perfect; obviously, the internal symbol system must lack many of the properties associated with a natural language. Nonetheless, like a natural language, the internal system’s formulae are taken to have subject/predicate form and to include logical devices, such as quantifiers and variables. In addition, the content of a complex symbol is supposed to be a function of its syntactic structure and the contents of its constituents. Returning to Sue’s beliefs, the supposition is that they are composed of such symbols as DAVE, CATHY and TALLER and that her beliefs represent what they do in virtue of the contents of these symbols and how they are arranged .