 The causal theorist can admit that some mental states are not about their causes, since some states are thoughts and thoughts mean what they do in virtue of, say, the meanings of mental sentences. These mental sentences might mean what they do in virtue of the meanings of primitive mental representations (which may or may not mean what they do in virtue of a causal theory of meaning) and the way in which those primitive mental representations are put together. As was mentioned in section 2, such a syntactically and semantically combinatorial language of thought is a familiar background assumption for causal theories. The conclusion that Buras may want, instead, is that there are some thoughts that do not mean what they do in virtue of what causes them. So, through some slight amendments, one can understand Buras to be presenting a clarification of the scope of causal theories of mental content or as a challenge to a particularly strong version of causal theories, a version that takes them as offering a necessary condition on meaning.