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.

The claim of this paper is that the everyday functions of knowledge make most sense if we see knowledge as contrastive. That is, we can best understand how the concept does what it does by thinking in terms of a relation “a knows that p rather than q.” There is always a contrast with an alternative. Contrastive interpretations of knowledge, and objections to them, have become fairly common in recent philosophy. The version defended here is fairly mild in that there (...) is no suggestion that we cannot think in terms of a simpler not explicitly contrastive relation “a knows that p.” Some, for instance Schaffer (2005) and Karjalainen and Morton (2003), have hinted that this stronger possibility may be right. But all that I am arguing now is that facts that are easily expressed in contrastive terms are vital to understanding why we need the concept of knowledge. In a piece that is in some ways a companion to this one ("Contrastivism" in Duncan Pritchard and Sven Bernecker, eds. The Routledge Companion to Epistemology. Routledge 2010, 513-522), I give a general survey of theories of contrastive knowledge and the differences between them. (shrink)

Knowledge and its Limits presents a systematic new conception of knowledge as a kind of mental stage sensitive to the knower's environment. It makes a major contribution to the debate between externalist and internalist philosophies of mind, and breaks radically with the epistemological tradition of analyzing knowledge in terms of true belief. The theory casts new light on such philosophical problems as scepticism, evidence, probability and assertion, realism and anti-realism, and the limits of what can be known. The arguments are (...) illustrated by rigorous models based on epistemic logic and probability theory. The result is a new way of doing epistemology and a notable contribution to the philosophy of mind. (shrink)

This paper revisits some foundational questions concerning the abstract representation of a discourse context. The context of a conversation is represented by a body of information that is presumed to be shared by the participants in the conversation – the information that the speaker presupposes a point at which a speech act is interpreted. This notion is designed to represent both the information on which context-dependent speech acts depend, and the situation that speech acts are designed to affect, and so (...) to be a representation of context that is appropriate for explaining the interaction of context and the contents expressed in them. After reviewing the motivating ideas and the outlines of the apparatus, the paper responds to a criticism of the framework, and considers the way it can help to clarify some phenomena concerning pronouns with indefinite antecedents. (shrink)

How should one understand knowledge-wh ascriptions? That is, how should one understand claims such as ‘‘I know where the car is parked,’’ which feature an interrogative complement? The received view is that knowledge-wh reduces to knowledge that p, where p happens to be the answer to the question Q denoted by the wh-clause. I will argue that knowledge-wh includes the question—to know-wh is to know that p, as the answer to Q. I will then argue that knowledge-that includes a contextually (...) implicit question. I will conclude that knowledge is a question-relative state. Knowing is knowing the answer, and whether one knows the answer depends (in part) on the question. (shrink)

Does G. E. Moore know that he has hands? Yes, says the dogmatist: Moore’s hands are right before his eyes. No, says the skeptic: for all Moore knows he could be a brain-in-a-vat. Yes and no, says the contrastivist: yes, Moore knows that he has hands rather than stumps; but no, Moore does not know that he has hands rather than vat-images of hands. The dogmatist and the skeptic suppose that knowledge is a binary, categorical relation: s knows that p. (...) The contrastivist says that knowledge is a ternary, contrastive relation: s knows that p rather than q. (shrink)

This essay invokes a technical framework of contrast classes within which Pyrrhonians can accept knowledge claims that are relativized to specific contrast classes, but avoid all unrelativized knowledge claims and all presuppositions about which contrast classes are really relevant. Pyrrhonians can then assert part of the content of everyday knowledge claims without privileging the everyday perspective or any other perspective. This framework provides a precise way to understand the central claims of neo-Pyrrhonism while avoiding most, if not all, of the (...) problems and objections raised by its critics. (shrink)

The skeptic says that “knowledge” is an absolute term, whereas the contextualist says that ‘knowledge” is a relationally absolute term. Which is the better hypothesis about “knowledge”? And what implications do these hypotheses about “knowledge” have for knowledge? I argue that the skeptic has the better hypothesis about “knowledge”, but that both hypotheses about “knowledge” have deeply anti‐skeptical implications for knowledge, since both presuppose our capacity for epistemically salient discrimination.

Paul Pietroski, in Causing Actions (2000), aims to articulate a dualistic framework that 'makes room for persons'. What is especially intriguing about Pietroski's framework is that it denies both of the above assumptions: (i) it is resolutely non-naturalistic, and (ii) it is a dualism of events, said to steer between substance and property dualisms. If Pietroski is right then both naturalism and the three-part taxonomy are worse than mistaken: they are in..

Contextualism treats ‘knows’ as an indexical that denotes different epistemic properties in different contexts. Contrastivism treats ‘knows’ as denoting a ternary relation with a slot for a contrast proposition. I will argue that contrastivism resolves the main philosophical problems of contextualism, by employing a better linguistic model. Contextualist insights are best understood by contrastivist theory.

Contextualists claim two important virtues for their view. First, contextualism is a non-skeptical epistemology, given the plausible idea that not all contexts invoke the high standards for knowledge needed to generate the skeptical conclusion that we know little or nothing. Second, contextualism is able to preserve closure concerning knowledge – the idea that knowledge is extendable on the basis of competent deduction from known premises. As long as one keeps the context fixed, it is plausible to think that some closure (...) principle can be articulated that will survive scrutiny. Opponents of contextualism often try to gain an advantage over it by claiming that their view mimics these virtues of contextualism as well as having other virtues. A recent example of the same is termed ‘contrastivism," as presented by Jonathan Schaffer. I will argue that the representation made is chimerical, that in fact contrastivism has no hope of mirroring these twin virtues of contextualism. (shrink)

We describe the three place relation of contrastive knowledge, which holds between a person, a target proposition, and a contrasting proposition. The person knows that p rather than that q. We argue for three claims about this relation. (a) Many common sense and philosophical ascriptions of knowledge can be understood in terms of it. (b) Its application is subject to fewer complications than non-contrastive knowledge is. (c) It applies over a wide range of human and nonhuman cases.

Radical skepticism, the view that no human being has any contingent knowledge of any external world there may be, has few adherents these days. But many who reject it concede that such skeptical arguments as SA require some sort of response, since they are obviously valid and their premises are, at the very least, highly plausible.

Knowledge and Lotteries is organized around an epistemological puzzle: in many cases, we seem consistently inclined to deny that we know a certain class of propositions, while crediting ourselves with knowledge of propositions that imply them. In its starkest form, the puzzle is this: we do not think we know that a given lottery ticket will be a loser, yet we normally count ourselves as knowing all sorts of ordinary things that entail that its holder will not suddenly acquire a (...) large fortune. After providing a number of specific and general characterizations of the puzzle, Hawthorne carefully examines the competing merits of candidate solutions. In so doing, he explores a number of central questions concerning the nature and importance of knowledge, including the relationship of knowledge to assertion and practical reasoning, the status of epistemic closure principles, the merits of various brands of scepticism, the prospects for a contextualist account of knowledge, and the potential for other sorts of salience-sensitive accounts. Along the way, he offers a careful treatment of pertinent issues at the foundations of semantics. His book will be of interest to anyone working in the field of epistemology, as well as to philosophers of language. (shrink)

Nozick analyzes fundamental issues, such as the identity of the self, knowledge and skepticism, free will, the foundations of ethics, and the meaning of life.

Throughout the history of philosophy, skepticism has posed one of the central challenges of epistemology. Opponents of skepticism--including externalists, contextualists, foundationalists, and coherentists--have focussed largely on one particular variety of skepticism, often called Cartesian or Academic skepticism, which makes the radical claim that nobody can know anything. However, this version of skepticism is something of a straw man, since virtually no philosopher endorses this radical skeptical claim. The only skeptical view that has been truly held--by Sextus, Montaigne, Hume, Wittgenstein, and, (...) most recently, Robert Fogelin--has been Pyrrohnian skepticism. Pyrrhonian skeptics do not assert Cartesian skepticism, but neither do they deny it. The Pyrrhonian skeptics' doubts run so deep that they suspend belief even about Cartesian skepticism and its denial. Nonetheless, some Pyrrhonians argue that they can still hold "common beliefs of everyday life" and can even claim to know some truths in an everyday way. This edited volume presents previously unpublished articles on this subject by a strikingly impressive group of philosophers, who engage with both historical and contemporary versions of Pyrrhonian skepticism. Among them are Gisela Striker, Janet Broughton, Don Garrett, Ken Winkler, Hans Sluga, Ernest Sosa, Michael Williams, Barry Stroud, Robert Fogelin, and Roy Sorensen. This volume is thematically unified and will interest a broad spectrum of scholars in epistemology and the history of philosophy. (shrink)

Much of the extant discussion focuses on the question of whether contextualism resolves skeptical paradoxes. Understandably. Yet there has been less discussion as to the internal structure of contextualist theories. Regrettably. Here, for instance, are two questions that could stand further discussion: (i) what is the linguistic basis for contextualism and (ii) what is the parameter that shifts with context?