In Chapter 1 we found a way of sidestepping the old and sterile problem of the ontological status of mental entities. In the place of an ontological division between phenomena or entities, we acknowledged only a division between the different things that we say, roughly characterized as a division between the mental language and the language of science, or physical language. In Chapter 2 this division was seen to coincide on a wide front, if not entirely, with the distinction between Intentional sentences and extensional sentences, and this raised a fundamental obstacle to our further efforts at relating mind to body, in the form of the Intentionalist thesis that it is logically impossible to ‘reduce’ the Intentional mode of discourse to the extensional. Acquiescence in this conclusion would leave large portions of our mental language discourse inexplicable in terms of the physical sciences. Two attempts to get around the Intentionalist thesis were found unpromising. Attempts at a purely extensional peripheralist science of behaviour have simply failed to marshall

their data into a working theory, and the failures bear all the earmarks of fundamental theoretical error; and an ‘autonomous science of Intention’ cannot co-exist with the rest of science. Since we apparently cannot do without the Intentional, and cannot allow it to remain irreducible, the only course left is a more direct assault on the Intentionalist thesis. The weak point in the arguments for the thesis was seen to be the reliance on overt, external behavioural cues as the benchmark of extensional correlates. Would an examination of internal states and events gain us any leverage over peripheralist accounts and allow us to prove the Intentionalist thesis wrong?