In this paper, I present and criticize a number of influential contemporary anti-skeptical strategies inspired by G.E. Moore’s “proof of an external world”. I argue that these accounts cannot represent a valid response to skeptical worries. Furthermore, drawing on Wittgenstein’s criticisms of Moore, I argue that Radical skeptical hypotheses should be considered nonsensical combinations of signs, excluded from our epistemic practices.

Extended Rationality: A Hinge Epistemology provides a novel account of the structure of epistemic justification. Its central claim builds upon Wittgenstein's idea in On Certainty that epistemic justifications hinge on some basic assumptions and that epistemic rationality extends to these very hinges. It exploits these ideas to address major problems in epistemology, such as the nature of perceptual justifications, external world skepticism, epistemic relativism, the epistemic status of basic logical laws, of the Principle of the Uniformity of Nature, of our (...) belief in the existence of the past and of other minds, and the nature of testimonial justification. Along the way, further technical issues, such as the scope of the Principle of Closure of epistemic operators under known entailment, the notion of transmission failure, and the existence of entitlements are addressed in new and illuminating ways. (shrink)

In this paper, I present and criticize a number of influential anti-skeptical strategies inspired by Wittgenstein’s remarks on ‘hinges’. Furthermore, I argue that, following Wittgen- stein’s analogy between ‘hinges’ and ‘rules of grammar’, we should be able to get rid of Cartesian skeptical scenarios as nonsensical, even if apparently intelligible, combinations of signs.

In this paper, I argue that arguments from skeptical hypotheses for external world skepticism derive their support from a skeptical argument from the distinction between appearance and reality. This skeptical argument from the appearance/reality distinction gives the external world skeptic her conclusion without appealing to skeptical hypotheses and without assuming that knowledge is closed under known entailments. If this is correct, then this skeptical argument from the appearance/reality distinction poses a new skeptical challenge that cannot be resolved by denying skeptical (...) hypotheses or knowledge closure. (shrink)