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.

I defend interest-relative invariantism from a number of recent attacks. One common thread to my response is that interest-relative invariantism is a muchweaker thesis than is often acknowledged, and a number of the attacks only challenge very specific, and I think implausible, versions of it. Another is that a number of the attacks fail to acknowledge how many things we have independent reason to believe knowledge is sensitive to. Whether there is a defeater for someone's knowledge can be sensitive to (...) all manner of features of their environment, as the host of examples from the post-Gettier literature shows. Adding in interest-sensitive defeaters is a much less radical move than most critics claim it is. (shrink)

Almost every contemporary theory of knowledge is a version of fallibilism, yet an adequate statement of fallibilism has not yet been provided. Standard definitions cannot account for fallibilistic knowledge of necessary truths. I consider and reject several attempts to resolve this difficulty before arguing that a belief is an instance of fallibilistic knowledge when it could have failed to be knowledge. This is a fully general account of fallibilism that applies to knowledge of necessary truths. Moreover, it reveals, not only (...) the connection between fallibility and error, but the connection between fallibility and accidental truth as well. (shrink)

A moral-pragmatic argument for a proposition is an argument intended to establish that believing the proposition would be morally beneficial. Since such arguments do not adduce epistemic reasons, i.e., reasons that support the truth of a proposition, they can seem at best to be irrelevant epistemically. At worst, believing on the basis of such reasoning can seem to involve wishful thinking and intellectual dishonesty of a sort that that precludes such beliefs from being epistemically unjustified. Inspired by an argument from (...) William James’ classic, “The Will to Believe”, I argue that there is a way of making sense of moral-pragmatic arguments such that they are epistemically relevant. I develop and argue for a theory of epistemic justification that I dub the “moral encroachment theory” (emphasizing its connection to recent pragmatic encroachment views). According to the theory, moral considerations can raise or lower epistemic standards from where they would be in morally neutral settings. The moral encroachment theory, I contend, denotes a normative property that is at once distinctively epistemic and valuable. The theory also allows a legitimate role for moral-pragmatic reasoning under certain conditions. The upshot is that moral-pragmatic reasoning can be epistemically as well as morally appropriate. (shrink)

We argue, contrary to epistemological orthodoxy, that knowledge is not purely epistemic—that knowledge is not simply a matter of truth‐related factors (evidence, reliability, etc.). We do this by arguing for a pragmatic condition on knowledge, KA: if a subject knows that p, then she is rational to act as if p. KA, together with fallibilism, entails that knowledge is not purely epistemic. We support KA by appealing to the role of knowledge‐citations in defending and criticizing actions, and by giving a (...) principled argument for KA, based on the inference rule KB: if a subject knows that A is the best thing she can do, she is rational to do A. In the second half of the paper, we consider and reject the two most promising objections to our case for KA, one based on the Gricean notion of conversational implicature and the other based on a contextualist maneuver. (shrink)

Judging by our folk appraisals, then, knowledge and action are intimately related. The theories of rational action with which we are familiar leave this unexplained. Moreover, discussions of knowledge are frequently silent about this connection. This is a shame, since if there is such a connection it would seem to constitute one of the most fundamental roles for knowledge. Our purpose in this paper is to rectify this lacuna, by exploring ways in which knowing something is related to rationally acting (...) upon it, defending one particular proposal against anticipated objections. (shrink)

According to ‘orthodox’ epistemology, it has recently been said, whether or not a true belief amounts to knowledge depends exclusively on truth-related factors: for example, on whether the true belief was formed in a reliable way, or was supported by good evidence, and so on. Jason Stanley refers to this as the ‘intellectualist’ component of orthodox epistemology, and Jeremy Fantl and Matthew McGrath describe it as orthodox epistemology’s commitment to a ‘purely epistemic’ account of knowledge — that is, an account (...) of knowledge where only truth-related factors figure in whether or not a person knows. In the first part of this paper I try to clarify the intellectualist thesis and to distinguish what I take to be its two main strains. In the remainder of the paper I then take a more critical turn and argue that even if, as a matter of fact, traditional epistemology has endorsed intellectualism in both of its strains, this is a mistake on the part of the tradition. At least one way of understanding intellectualism should be rejected and its practicalist counterpart should be accepted instead. (shrink)

Introduction -- Fallibilism -- Contextualism -- Knowledge and reasons -- Justification -- Belief -- The value and importance of knowledge -- Infallibilism or pragmatic encroachment? -- Appendix I: Conflicts with bayesian decision theory? -- Appendix II: Does KJ entail infallibilism?

Evidentialism is the thesis that epistemic justification for belief supervenes on evidential support. However, we claim there are cases in which, even though two subjects have the same evidential support for a proposition, only one of them is justified. What make the difference are pragmatic factors, factors having to do with our cares and concerns. Our argument against evidentialism is not based on intuitions about particular cases. Rather, we aim to provide a theoretical basis for rejecting evidentialism by defending a (...) “pragmatic” necessary condition on epistemic justification. We argue for the following necessary condition for justification: S is justified in believing that p only if S is rational to prefer (and, hence, act) as if p. In light of this necessary condition, the price of evidentialism is skepticism, or something close to it. (shrink)

The standard philosophical project of analysing the concept of knowledge has radical defects in its arbitrary restriction of the subject matter, and its risky theoretical presuppositions. Edward Craig suggests a more illuminating approach, akin to the `state of nature' method found in political theory, which builds up the concept from a hypothesis about the social function of knowledge and the needs it fulfils. Light is thrown on much that philosophers have written about knowledge, about its analysis and the obstacles to (...) its analysis, and on the debate over scepticism. It becomes apparent why many languages not only have such constructions as `knows whether' and `knows that', but also have equivalents of `knows how to' and `know' followed by a direct object. Thus the inquiry is both broadened in scope and made theoretically less fragile. (shrink)