 The autonomy of the special sciences from physics has been defended in terms of a distinction between type-physicalism and token-physicalism (Fodor 1974; Fodor countered Oppenheim and Putnam’s hypothesis under the rubric “the disunity of science”; the entry on  physicalism).  The key logical assumption is the type-token distinction, that types are realized by more specific tokens, e.g., the type animal is instantiated by different species, the type tiger or electron can be instantiated by multiple individual token tigers and electrons. Type-physicalism is characterized by a type-type identity between the predicates/properties in the laws of the special sciences and those of physics. By contrast, token-physicalism is based on the token-token identity between the predicates/properties of the special sciences and those of physics; every event under a special law falls under a law of physics and bridge laws express contingent token-identities between events. Token-physicalism operates as a demarcation criterion for materialism. Fodor argued that the predicates of the special sciences correspond to infinite or open-ended disjunctions of physical predicates, and these disjunctions do not constitute natural kinds identified by an associated law. Token-physicalism is the only alternative. All special kinds of events are physical but the special sciences are not physics (for criticisms based on the presuppositions in Fodor’s argument, see Sober 1999).