Locating thought: Externalism and naturalism about mental content

Externalism about mental content is the view that the contents of thoughts constitutively depend on the thinker's causal relations to the surrounding world. While externalism is most commonly defended by appeal to thought experiments purporting to show that causal relations to the environment individuate particular kinds of content, some philosophers argue for externalism on the basis of the claim that certain causal relations to the environment are necessary for the very capacity to think about the world at all. My project is to see whether this claim, which we may usefully think of as 'transcendental', can be sustained.;One route to the transcendental claim is provided by 'semantic naturalism', the doctrine that facts about mental content reduce to facts expressible in non-mentalistic terms. The claim follows if we suppose, as do most semantic naturalists, that the relevant non-mentalistic facts concern relationships between inner states and items in the external world. Typically, naturalists look to relationships whose existence is predicted by, or at least obviously consistent with, the familiar belief-desire psychology that we bring to bear in our everyday assessments of the thoughts and actions of others. The problem, I argue, is that taking content to reduce to the existence of such relations would force us to abandon our ordinary explanations of why these relations hold. I first develop this case against 'informational semantics', as elaborated by Jerry Fodor and others, and then against 'teleofunctionalism', as represented by the views of Fred Dretske.;Can we motivate the transcendental claim without presupposing semantic naturalism? Donald Davidson argues that acquisition of the concept of objective truth, and so of the capacity to entertain any thoughts and beliefs at all, requires interaction with other creatures in a shared environment. He offers two arguments in support of this contention, but I show that both depend on an unmotivated leap from epistemic premises to metaphysical conclusions.;In the wake of these failures, is there any hope for a successful argument for the transcendental claim? We can come as close as I believe is possible to such an argument from consideration of Kripke's discussion of rule following. The core of the argument is Kripke's insight that acting on one's understanding cannot involve being guided by one's understanding. Kripke himself wrongly supposes that the failure of the 'guiding' conception undermines the very idea that people mean and understand things. I trace his mistake to a misunderstanding of the role of community practice: whereas Kripke looks to the communal setting only in the aftermath of his irrealist conclusion, the right appeal to community practice will show why this conclusion never needed to be drawn. The upshot of this appeal is a conception of mental life that falls short of the transcendental claim, but is nonetheless opposed to an influential strain in contemporary philosophy of mind that invites the label, 'internalism'. This result suggests that we need to rethink our understanding of what is really the fundamental disagreement or opposition in this area of the philosophy of mind.