Here is a forthcoming paper from the VERY excellent Brie Gertler.
Since the work of Burge, Davidson, Kripke, and Putnam in the 1970’s, philosophers of language and mind have engaged in extensive debate over the following question: Do mental content properties—such as thinking that water quenches thirst—supervene on properties intrinsic to the thinker? To answer affirmatively is to endorse internalism (or “individualism”); a negative answer is an expression of externalism. There is no consensus about the correct answer to this question; a 2009 survey indicates that a bare majority of philosophers now characterize themselves as externalists.1 The recent literature on this topic largely focuses on the implications of externalism and internalism. There is no consensus here either. Philosophers are sharply divided as to whether externalism is compatible with privileged access to one’s own thoughts; whether externalism implies that we can achieve knowledge of the external world from the armchair; whether internalism is compatible with physicalism about the mental; and whether internalism implies that thoughts are incommunicable. Disagreements are philosophers’ stock in trade. But the disputes just mentioned have proven exceptionally intractable. The culprit, I think, is an ambiguity in the terms “externalism” and “internalism”, which they inherit from an ambiguity in the notion of “intrinsic to the thinker” operative in these disputes. As employed in the debate over mental content, “externalism” and “internalism” are associated with a shifting set of claims encompassing a heterogeneous array of topics; these include the organism’s contribution to thought contents, links between the individual and her community, the epistemic availability of thoughts, and relations between phenomenal character and intentional content. I will argue that this ambiguity is ineliminable. Any way of explicating “intrinsic to the thinker” will clash with the usual taxonomy of leading externalist and internalist views, or construe these positions as involving claims that are standardly regarded as orthogonal to them—and, in some cases, explicitly rejected by their most prominent exponents.2 The moral is stark. The sense that there is a substantive, defining commitment of externalism or internalism—even one that is vague or underspecified—is illusory. There is no univocal thesis of externalism or internalism. The ambiguity of “externalism” and “internalism” helps to explain why contributors to this literature often seem to be arguing at cross-purposes, disagreeing about the truth and implications of externalism and internalism, and about the nature of the evidence that could resolve these disputes. Now this ambiguity would not be too worrisome if its effects were confined to disputes about mental content. But because the claims associated with externalism and internalism cover a diverse range of topics, philosophers routinely invoke externalism or internalism (or purported implications thereof) in evaluating a range of other questions—in the 2 philosophy of language, epistemology, and the philosophy of mind. These include: Does the meaning of an utterance correspond to elements understood by the speaker? Do thinkers generally enjoy privileged access to their own mental states? Can we know contingent facts about the external world through introspection and a priori reasoning? Does phenomenal character supervene on intentional content, or vice versa? Can content be naturalized? The ambiguity endemic to discussions of externalism and internalism thus threatens progress on a broad spectrum of philosophical questions.