 The second type of argument against beliefs focuses upon their semantic properties and concludes that these sorts of properties make propositional attitudes ill-suited for even a computational theory of the mind. Stephen Stich (1983) has emphasized that folk psychology individuates beliefs by virtue of their semantic properties, e.g., we taxonomize states like beliefs by virtue of what they are about. However, according to Stich, there are a host of reasons for rejecting a semantic taxonomy for scientific psychology. Semantic taxonomies ignore causally salient aspects of cognitive states, involve a high degree of vagueness, and break down in the case of the mentally ill or the very young. In place of the semantic individuation method adopted by folk psychology, Stich argues for a syntactic taxonomy that is based upon the causally relevant syntactic or physical properties of a given cognitive state.