 Externalism and Mind-Body Theories. Externalism has important consequences for a number of different mind-body theories. Burge (1979) believes that externalism refutes individualistic theories of intentional mental states. These are theories that define or explain what it is for a person to have an intentional mental state purely in terms of intrinsic facts about that person without reference to the environment. Examples of such theories include the identity theory, and  functionalism (see entry)  in its traditional guise. McGinn (1989) and Burge (1986, 1993) both argue that externalism refutes the token-identity theory (and hence the type-identity theory as well). This is contested by Davidson (1987), Macdonald (1990) Gibbons (1993), and Frances (2007). With regard to functionalism, one way to deal with externalism is to adopt a divide-and-conquer strategy. One might restrict functionalism to providing an account of what it is to be a particular kind of mental state (e.g., a belief) individualistically, while adopting an externalist theory of content (Fodor 1987). Alternatively, one might adopt a “long arm” functionalism that specifies functional roles in such a way that they incorporate worldly items and properties (Block 1990). On such a view, the functional role of your belief that water is wet would be different from the functional role of your twin’s belief that twater is wet, on the grounds that the functional role of your belief involves you perceiving and doing things with water whereas that of your twin involves her perceiving and doing things with twater.