ABSTRACT. Our aim is to provide a topography of the relevant philosophical terrain with regard to the possible ways in which knowledge can be conceived of as extended. We begin by charting the different types of internalist and externalist proposals within epistemology, and we critically examine the different formulations of the epistemic internalism/externalism debate they lead to. Next, we turn to the internalism/externalism distinction within philosophy of mind and cognitive science. In light of the above dividing lines, we then examine first the extent to which content externalism is compatible with epistemic externalism; second, whether active externalism entails epistemic externalism; and third whether there are varieties of epistemic externalism that are better suited to accommodate active externalism. Finally, we examine whether the combination of epistemic and cognitive externalism is necessary for epistemology and we comment on the potential ramifications of this move for social epistemology and philosophy of science.
INTRODUCTIONThe distinction between internalism and externalism is common to both contemporary philosophy of mind and contemporary epistemology, and it is the central topic of ongoing debates in both disciplines. To a certain extent this is unsurprising, given that these two theoretical domains are closely related in that they both focus on the study of cognitive phenomena.Despite the appearance of such common grounds, however, there are several differences between these two fields of study. Arguably, the most important one is that philosophy of mind studies cognition in a more inclusive way, by considering all kinds of mental states and processes (e.g., experience, beliefs, desires, emotions and so on), whereas epistemology focuses on the cognitive process of knowledge-acquisition and its cognates (e.g., belief and justification).Accordingly, it would be unsafe to assume that the internalism/externalism distinction maps on to both disciplines in the exact same way. And, indeed, it doesn't. Briefly stated, on the one hand, the internalism/externalism distinction, as it is normally construed within contemporary epistemology, refers to the debate over whether an agent's justification for believing a proposition p should always be (at least in principle) accessible to him by reflection alone. In other words, epistemic internalists hold that one's justification should always be internal to one's conscious mind, whereas epistemic externalists deny this claim.1 On the other hand, the standard way of thinking about the internalism/externalism debate within philosophy of mind is that internalists hold that cognitive processes and mental states reside exclusively within the agent's head, whereas externalists deny this on multiple grounds and with several degrees of departure from the internalist position.Embodied cognition theorists, for example, hold that several mental processes and states (e.g., experience, emotions and desires) may be constitutively dependent not only on the agent's brain but ...