The demon that makes us go mental: mentalism defended

Abstract

Facts about justification are not brute facts. They are epistemic facts that depend upon more fundamental non-epistemic facts. Internalists about justification often argue for mentalism, which claims that facts about justification supervene upon one’s non-factive mental states, using Lehrer and Cohen’s (Synthese 55(2):191–207, 1983) New Evil Demon Problem. The New Evil Demon Problem tells you to imagine yourself the victim of a Cartesian demon who deceives you about what the external world is like, and then asks whether you nevertheless have justification for your beliefs about the external world. Internalists and externalists agree that there is something that is epistemically good or valuable about both your actual beliefs and your beliefs in the demon scenario. Internalists claim that the epistemic property which these sets of beliefs share most intuitively should be thought of as sameness of justification. Externalists, on the other hand, reject this claim, usually either by challenging the internalist intuition directly, or by arguing that there is a more plausible way to think about the epistemic property in question. Recently, both kinds of externalist objection have been raised against the argument from the New Evil Demon Problem for mentalism. The goal of this paper is to defend the argument against three prominent objections—a pair of which is offered by Littlejohn (Can J Philos 39(3):399–434, 2009) and one by Williamson (in: Timmons M, Greco J, Mele A (eds.) Rationality and the good: critical essays on the ethics and epistemology of Robert Audi, Oxford University Press, Oxford, 2007; in: Dutant J, Dohrn D (eds.) The new evil demon, Oxford University Press, Oxford, 2016).