This paper compares two kinds of epistemic principles---an underdetermination principle and a deductive closure principle. It argues that each principle provides the basis for an independently motivated skeptical argument. It examines the logical relations between the premises of the two kinds of skeptical argument and concludes that the deductive closure argument cannot be refuted without refuting the underdetermination argument. The underdetermination argument, however, can be refuted without refuting the deductive closure argument. In this respect, the deductive closure argument is the (...) stronger of the two. (shrink)

Much has been written about epistemological skepticism in the last ten or so years, but there remain some unanswered questions concerning the structure of what has become the canonical Cartesian skeptical argument. In this paper, I would like to take a closer look at this structure in order to determine just which epistemic principles are required by the argument.

David Lewis (1941-2001) was Class of 1943 University Professor of Philosophy at Princeton University. His contributions spanned philosophical logic, philosophy of language, philosophy of mind, philosophy of science, metaphysics, and epistemology. In On the Plurality of Worlds, he defended his challenging metaphysical position, "modal realism." He was also the author of the books Convention, Counterfactuals, Parts of Classes, and several volumes of collected papers.

Stephen Schiffer; XIII*—Contextualist Solutions to Scepticism, Proceedings of the Aristotelian Society, Volume 96, Issue 1, 1 June 1996, Pages 317–334, https://.

Rieber 1998 proposes an account of "S knows that p" that generates a contextualist solution to Closure. In this paper, I’ll argue that Rieber’s account of "S knows that p" is subject to fatal objections, but we can modify it to achieve an adequate account of "S knows that p" that generates a unified contextualist solution to all four puzzles. This is a feat that should matter to those philosophers who have proposed contextualist solutions to Closure: all of them have (...) motivated their contextualism by appeal to the fact that they can explain the plausibility of each of the statements in Closure taken individually, and they can do this without having to deny that each of those statements is true, at least in the context in which it is plausible. But notice that this consideration would equally well motivate a contextualist approach to the other puzzles. Nonetheless, no contextualist has yet suggested how a contextualist solution to the other puzzles might go. (shrink)

A skeptic claims that I do not have knowledge of the external world. It has been thought that the skeptic reaches this conclusion because she employs unusually stringent standards for knowledge. But the skeptic does not employ unusually high standards for knowledge. Rather, she employs unusually restrictive standards of evidence. Thus, her claim that we lack knowledge of the external world is supported by considerations that would equally support the claim that we lack evidence for our beliefs about the external (...) world. These considerations do not threaten the truth of our ordinary attributions of evidence, however, for such attributions are context-sensitive in their semantics. It is argued that this solution to the problem of the external world enjoys all of the benefits, and suffers none of the problems, of other solutions to the problem of the external world. (shrink)

A skeptic claims that I do not have knowledge of the external world. It has been thought that the skeptic reaches this conclusion because she employs unusually stringent standards for knowledge. But the skeptic does not employ unusually high standards for knowledge. Rather, she employs unusually restrictive standards of evidence. Thus, her claim that we lack knowledge of the external world is supported by considerations that would equally support the claim that we lack evidence for our beliefs about the external (...) world. These considerations do not threaten the truth of our ordinary attributions of evidence, however, for such attributions are context‐sensitive in their semantics.It is argued that this solution to the problem of the external world enjoys all of the benefits. and suffers none of the problems, of other solutions to the problem of the external world. (shrink)

The relevant alternatives approach in epistemology1 arose some years ago partly out of the hope to be able to reconcile our ordinary claims of knowledge with our inability to answer the skeptic. It was supposed to give rise to an account of knowledge according to which our ordinary claims of knowledge are true, even though the claims about our lack of knowledge that the skeptics make in one of their more persuasive moments are also true. To know, according to such (...) an account, is to have evidence sufficient to rule out all the relevant alternatives. In ordinary life few alternatives are relevant. For example, whether or not we are brains in a vat is not a relevant alternative that we have to be able to rule out. In the debate with the skeptic it may become relevant, and accordingly we might not know something any more then, even though we have the same evidence as in ordinary life. The skeptics cleverly make more and more alternatives relevant, and that is how they succeed. But their success in the philosophy seminar is no threat to our ordinary claims of knowledge, or so the theory goes. (shrink)