 Like its competitors, Horwich’s theory is also open to some objections. One might worry that his use of the sentential attitude of acceptance entails a lapse into mentalism, if acceptance either just is, or is analyzed in terms of, beliefs. There is also a worry—which affects other “use” or “conceptual role” or “functional role” theories of meaning—that Horwich’s account implies the existence of differences in meaning which do not exist; it seems, for example, that two people’s use of some term might be explained by distinct basic acceptance regularities without their meaning different things by that term. Schiffer (2000) discusses the example of “dog”, and the differences between the basic acceptance regularities which govern the use of the term for the blind, the biologically unsophisticated, and people acquainted only with certain sorts of  dogs.[7]