Externalism before language: The real reason why “thoughts ain’t in the head”

It is argued that standard arguments for the Externalism of mental states do not succeed in the case of pre-linguistic mental states. Further, it is noted that standard arguments for Internalism appeal to the principle that our in-dividuation of mental states should be driven by what states are explanatory in our best cognitive science. This principle is used against the Internalist to reject the necessity of narrow individuation of mental states, even in the pre-linguistic case. This is done by showing how the explanation of some phenom-ena requires quantification over broadly-individuated, world-involving states; sometimes externalism is required. Although these illustrative phenomena are not mental, they are enough to show the general argumentative strategy to be incorrect: scientific explanation does not require narrowly-individuated states. Over twelve years ago, Jerry Fodor considered Methodological Solipsism as a re-search strategy for cognitive psychology [Fodor, 1981]. By “Methodological Solipsism”, he meant the belief that