 Reductive PIT stands in contrast with two well-known classes of reductive theories of intentionality: tracking theories (Stampe 1977, Dretske 1988, 1995, Millikan 1984, Fodor 1987), which take the content of mental states to be a matter of causal-informational-historical links between them and things in the environment (see the entries on  causal theories of mental content  and  teleological theories of mental content),  and conceptual role theories, which take the content of mental states to be a matter of their relations to other mental states and sometimes to the external world (Block 1986, Harman 1987, Greenberg &amp; Harman 2007). (See the section  Conceptual role  in the entry on  narrow mental content.)  Reductive PIT also contrasts with primitivism, the view that intentionality cannot be reduced.