This book explores a question central to philosophy--namely, what does it take for a belief to be justified or rational? According to a widespread view, whether one has justification for believing a proposition is determined by how probable that proposition is, given one's evidence. In this book this view is rejected and replaced with another: in order for one to have justification for believing a proposition, one's evidence must normically support it--roughly, one's evidence must make the falsity of that proposition (...) abnormal in the sense of calling for special, independent explanation. This conception of justification bears upon a range of topics in epistemology and beyond. Ultimately, this way of looking at justification guides us to a new, unfamiliar picture of how we should respond to our evidence and manage our own fallibility. This picture is developed here. (shrink)

Infallibilism is the view that a belief cannot be at once warranted and false. In this essay we assess three nonpartisan arguments for infallibilism, arguments that do not depend on a prior commitment to some substantive theory of warrant. Three premises, one from each argument, are most significant: if a belief can be at once warranted and false, then the Gettier Problem cannot be solved; if a belief can be at once warranted and false, then its warrant can be transferred (...) to an accidentally true belief; if a belief can be at once warranted and false, then it can be warranted and accidentally true. We argue that each of these is either false or no more plausible than its denial. Along the way, we offer a solution to the Gettier Problem that is compatible with fallibilism. (shrink)

Ernest Sosa has argued that if someone knows that p, then his belief that p is “safe”. and Timothy Williamson has agreed. In this paper I argue that safety, as defined by Sosa, is not a necessary condition on knowledge – that we can have unsafe knowledge. I present Sosa’s definition of safety and a counterexample to it as a necessary condition on knowledge. I also argue that Sosa’s most recent refinements to the notion of safety don’t help him to (...) avoid the counterexample. I consider three replies on behalf of the defender of safety, and find them all wanting. Finally, I offer a tentative diagnosis of my counterexample. (shrink)

We distinguish between two categories of belief—thin belief and thick belief—and provide evidence that they approximate genuinely distinct categories within folk psychology. We use the distinction to make informative predictions about how laypeople view the relationship between knowledge and belief. More specifically, we show that if the distinction is genuine, then we can make sense of otherwise extremely puzzling recent experimental findings on the entailment thesis (i.e. the widely held philosophical thesis that knowledge entails belief). We also suggest that the (...) distinction can be applied to debates in the philosophy of mind and metaethics. (shrink)

Many contemporary epistemologists hold that a subject S’s true belief that p counts as knowledge only if S’s belief that p is also, in some important sense, safe. I describe accounts of this safety condition from John Hawthorne, Duncan Pritchard, and Ernest Sosa. There have been three counterexamples to safety proposed in the recent literature, from Comesaña, Neta and Rohrbaugh, and Kelp. I explain why all three proposals fail: each moves fallaciously from the fact that S was at epistemic risk (...) just before forming her belief to the conclusion that S’s belief was formed unsafely. In light of lessons from their failure, I provide a new and successful counterexample to the safety condition on knowledge. It follows, then, that knowledge need not be safe. Safety at a time depends counterfactually on what would likely happen at that time or soon after in a way that knowledge does not. I close by considering one objection concerning higher-order safety. (shrink)

Warrant is what fills the gap between mere true belief and knowledge. But a problem arises. Is there just one condition that satisfies this description? Suppose there isn’t: can anything interesting be said about warrant after all? Call this the uniqueness problem. In this paper, I solve the problem. I examine one plausible argument that there is no one condition filling the gap between mere true belief and knowledge. I then motivate and formulate revisions of the standard analysis of warrant. (...) Given these revisions, I argue that there is, after all, exactly one warrant condition. (shrink)

One thousand fair causally isolated coins will be independently flipped tomorrow morning and you know this fact. I argue that the probability, conditional on your knowledge, that any coin will land tails is almost 1 if that coin in fact lands tails, and almost 0 if it in fact lands heads. I also show that the coin flips are not probabilistically independent given your knowledge. These results are uncomfortable for those, like Timothy Williamson, who take these probabilities to play a (...) central role in their theorizing. (shrink)

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.

It is widely acknowledged that epistemic modals admit of inter-subjective flexibility. This paper introduces intra-subjective flexibility for epistemic modals and draws on this flexibility to argue that fallibilism is consistent with the standard account of epistemic modals.

A Virtue Epistemology presents a new approach to some of the oldest and most gripping problems of philosophy, those of knowledge and scepticism. Ernest Sosa argues for two levels of knowledge, the animal and the reflective, each viewed as a distinctive human accomplishment. By adopting a kind of virtue epistemology in line with the tradition found in Aristotle, Aquinas, Reid, and especially Descartes, he presents an account of knowledge which can be used to shed light on different varieties of scepticism, (...) the nature and status of intuitions, and epistemic normativity. (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)

Edmund Gettier is Professor Emeritus at the University of Massachusetts, Amherst. This short piece, published in 1963, seemed to many decisively to refute an otherwise attractive analysis of knowledge. It stimulated a renewed effort, still ongoing, to clarify exactly what knowledge comprises.

Many epistemologists call themselves ‘fallibilists’. But many philosophers of language hold that the meaning of epistemic usages of ‘possible’ ensures a close knowledge- possibility link : a subject’s utterance of ‘it’s possible that not-p’ is true only if the subject does not know that p. This seems to suggest that whatever the core insight behind fallibilism is, it can’t be that a subject could have knowledge which is, for them, possibly false. I argue that, on the contrary, subjects can have (...) such possibly false knowledge. My ultimate aim, then, is to vindicate a very robust form of fallibilism. Uniquely, however, the account I offer does this while also allowing that concessive knowledge attributions – sentences of the form “I know that p, but it’s possible that not-p” – are not only infelicitous but actually false whenever uttered. The account predicts this result without conceding KPL. I argue that my account has the resources to explain some related cases for which the KPL account yields the wrong predictions. Taken as a whole, the linguistic data not only do not support the proposal that subjects cannot have possibly false knowledge, but indeed positively favor the proposal that they can. (shrink)

An intellectual virtue is a quality bound to help maximize one’s surplus of truth over error; or so let us assume for now, though a more just conception may include as desiderata also generality, coherence, and explanatory power, unless the value of these is itself explained as derivative from the character of their contribution precisely to one’s surplus of truth over error. This last is an issue I mention in order to lay it aside. Here we assume only a teleological (...) conception of intellectual virtue, the relevant end being a proper relation to the truth, exact requirements of such propriety not here fully specified. (shrink)

What modal relation must a fact bear to a belief in order for this belief to constitute knowledge of that fact? Externalists have proposed various answers, including some that combine externalism with contextualism. We shall find that various forms of externalism share a modal conception of “sensitivity” open to serious objections. Fortunately, the undeniable intuitive attractiveness of this conception can be explained through an easily confused but far preferable notion of “safety.” The denouement of our reflections, finally, will be to (...) show how replacing sensitivity with safety makes it possible to defend plain Moorean common sense against the spurious advantages over it claimed by skeptical, tracking, relevant-alternative, and contextualist accounts. (shrink)

Ernest Sosa's A Virtue Epistemology, Vol. I is arguably the single-most important monograph to be published in analytic epistemology in the last ten years. Sosa, the first in the field to employ the notion of intellectual virtue – in his ground-breaking ‘The Raft and the Pyramid’– is the leading proponent of reliabilist versions of virtue epistemology. In A Virtue Epistemology, he deftly defends an externalist account of animal knowledge as apt belief, argues for a distinction between animal and reflective knowledge, (...) contends that rational intuition is an intellectual virtue ; and offers responses to dream scepticism, the problem of the criterion and the value problem. Nearly all of these arguments are new, albeit consistent with Sosa's earlier work; that is, consistent with two notable exceptions. First, c ontra Sosa's ‘Replies’ in Ernest Sosa and His Critics, A Virtue Epistemology explicitly contends that safety is not required for animal knowledge. Second, unlike Sosa's Knowledge in Perspective, which arguably construes the intellectual virtues as merely instrumentally valuable, A Virtue Epistemology explicitly contends that the intellectual virtues are instrumentally and constitutively valuable. Best read in conjunction with the above monographs and Epistemic Justification, A Virtue Epistemology is mandatory reading for epistemologists and graduate students in the field. It will rightly set the standard for debates in analytic epistemology for years to come.I will summarize and raise objections to two key conclusions that are unique to A Virtue Epistemology: the ‘kaleidoscope-perceiver’ has animal knowledge but lacks reflective knowledge; unlike the k-perceiver, the ordinary perceiver has reflective knowledge. My objections …. (shrink)

According to a captivating picture, epistemic justification is essentially a matter of epistemic or evidential likelihood. While certain problems for this view are well known, it is motivated by a very natural thought—if justification can fall short of epistemic certainty, then what else could it possibly be? In this paper I shall develop an alternative way of thinking about epistemic justification. On this conception, the difference between justification and likelihood turns out to be akin to the more widely recognised difference (...) between ceteris paribus laws and brute statistical generalisations. I go on to discuss, in light of this suggestion, issues such as classical and lottery-driven scepticism as well as the lottery and preface paradoxes. (shrink)

The idea that knowledge can be extended by inference from what is known seems highly plausible. Yet, as shown by familiar preface paradox and lottery-type cases, the possibility of aggregating uncertainty casts doubt on its tenability. We show that these considerations go much further than previously recognized and significantly restrict the kinds of closure ordinary theories of knowledge can endorse. Meeting the challenge of uncertainty aggregation requires either the restriction of knowledge-extending inferences to single premises, or eliminating epistemic uncertainty in (...) known premises. The first strategy, while effective, retains little of the original idea—conclusions even of modus ponens inferences from known premises are not always known. We then look at the second strategy, inspecting the most elaborate and promising attempt to secure the epistemic role of basic inferences, namely Timothy Williamson’s safety theory of knowledge. We argue that while it indeed has the merit of allowing basic inferences such as modus ponens to extend knowledge, Williamson’s theory faces formidable difficulties. These difficulties, moreover, arise from the very feature responsible for its virtue- the infallibilism of knowledge. (shrink)

Knowledge is widely thought to entail belief. But Radford has claimed to offer a counterexample: the case of the unconfident examinee. And Myers-Schulz and Schwitzgebel have claimed empirical vindication of Radford. We argue, in defense of orthodoxy, that the unconfident examinee does indeed have belief, in the epistemically relevant sense of dispositional belief. We buttress this with empirical results showing that when the dispositional conception of belief is specifically elicited, people’s intuitions then conform with the view that knowledge entails (dispositional) (...) belief. (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)

Consider the skeptic about the external world. Let’s straightaway concede to such a skeptic that perception gives us no conclusive or certain knowledge about our surroundings. Our perceptual justification for beliefs about our surroundings is always defeasible—there are always possible improvements in our epistemic state which would no longer support those beliefs. Let’s also concede to the skeptic that it’s metaphysically possible for us to have all the experiences we’re now having while all those experiences are false. Some philosophers dispute (...) this, but I do not. The skeptic I want to consider goes beyond these familiar points to the much more radical conclusion that our perceptual experiences can’t give us any knowledge or even justification for believing that our surroundings are one way rather than another. (shrink)

One of the key supposed 'platitudes' of contemporary epistemology is the claim that knowledge excludes luck. One can see the attraction of such a claim, in that knowledge is something that one can take credit for - it is an achievement of sorts - and yet luck undermines genuine achievement. The problem, however, is that luck seems to be an all-pervasive feature of our epistemic enterprises, which tempts us to think that either scepticism is true and that we don't know (...) very much, or else that luck is compatible with knowledge after all. In this book, Duncan Pritchard argues that we do not need to choose between these two austere alternatives, since a closer examination of what is involved in the notion of epistemic luck reveals varieties of luck that are compatible with knowledge possession and varieties that aren't. Moreover, Pritchard shows that a more nuanced understanding of the relationship between luck and knowledge can cast light on many of the most central topics in contemporary epistemology. These topics include: the externalism/internalism distinction; virtue epistemology; the problem of scepticism; metaepistemological scepticism; modal epistemology; and the problem of moral luck. All epistemologists will need to come to terms with Pritchard's original and incisive contribution. (shrink)

In his recent Knowledge and its Limits, Timothy Williamson argues that no non-trivial mental state is such that being in that state suffices for one to be in a position to know that one is in it. In short, there are no “luminous” mental states. His argument depends on a “safety” requirement on knowledge, that one’s confident belief could not easily have been wrong if it is to count as knowledge. We argue that the safety requirement is ambiguous; on one (...) interpretation it is obviously true but useless to his argument, and on the other interpretation it is false. (shrink)

Most epistemologists hold that knowledge entails belief. However, proponents of this claim rarely offer a positive argument in support of it. Rather, they tend to treat the view as obvious and assert that there are no convincing counterexamples. We find this strategy to be problematic. We do not find the standard view obvious, and moreover, we think there are cases in which it is intuitively plausible that a subject knows some proposition P without—or at least without determinately—believing that P. Accordingly, (...) we present five plausible examples of knowledge without (determinate) belief, and we present empirical evidence suggesting that our intuitions about these scenarios are not atypical. (shrink)

The standard view in epistemology is that propositional knowledge entails belief. Positive arguments are seldom given for this entailment thesis, however; instead, its truth is typically assumed. Against the entailment thesis, Myers-Schulz and Schwitzgebel (Noûs, forthcoming) report that a non-trivial percentage of people think that there can be propositional knowledge without belief. In this paper, we add further fuel to the fire, presenting the results of four new studies. Based on our results, we argue that the entailment thesis does not (...) deserve the default status that it is typically granted. We conclude by considering the alternative account of knowledge that Myers-Schulz and Schwitzgebel propose to explain their results, arguing that it does not explain ours. In its place we offer a different explanation of both sets of findings—the conviction account, according to which belief, but not knowledge, requires mental assent. (shrink)

Let ‘warrant’ denote whatever precisely it is that makes the difference between knowledge and mere true belief. A current debate in epistemology asks whether warrant entails truth, i.e., whether (Infallibilism) S’s belief that p is warranted only if p is true. The arguments for infallibilism have come under considerable and, as of yet, unanswered objections. In this paper, I will defend infallibilism. In Part I, I advance a new argument for infallibilism; the basic outline is as follows. Suppose fallibilism is (...) true. An implication of fallibilism is that the property that makes the difference between knowledge and mere belief (which I dub ‘warrant*’) is the conjunctive property being warranted and true . I show that this implication of fallibilism conflicts with an uncontroversial thesis we have learned from reflection on Gettier cases: that nonaccidental truth is a constituent of warrant*. It follows that infallibilism is true. In the second part of the paper, I present and criticize a new argument against infallibilism. The argument states that there are plausible cases where, intuitively, the only thing that is keeping a belief from counting as knowledge is the falsity of that belief. Furthermore, it is plausible that such a belief is warranted and false. So, the argument goes, infallibilism is false. I show that this argument fails. (shrink)

Warrant is “that, whatever precisely it is, which makes the difference between knowledge and mere true belief.” S knows that p, therefore, if and only if S’s belief that p is warranted and p is true. This is a purely formal characterization of warrant. Warrant may, no doubt, be a messy item: a substantive analysis might be full of disjuncts and conjuncts and conditionals and caveats. But if there are true beliefs that are not knowledge, then there is something that (...) all beliefs that are knowledge share, and all merely true beliefs lack. This is warrant. I want to argue that warrant, whatever it is that makes the difference between mere true belief and knowledge, entails truth. (shrink)

This essay motivates a revised version of the epistemic condition of safety and then employs the revision to (i) challenge traditional conceptions of apriority, (ii) refute ‘strong privileged access’, and (iii) resolve a well-known puzzle about externalism and self-knowledge.

This paper raises a problem for so-called safety-based conceptions of knowledge: It is argued that none of the versions of the safety condition that can be found in the literature succeeds in identifying a necessary condition on knowledge. Furthermore, reason is provided to believe that the argument generalizes at least in the sense that there can be no version of the safety condition that does justice to the considerations motivating a safety condition whilst, at the same time, being requisite for (...) knowledge. (shrink)

This paper raises a problem for so-called safety-based conceptions of knowledge: It is argued that none of the versions of the safety condition that can be found in the literature succeeds in identifying a necessary condition on knowledge. Furthermore, reason is provided to believe that the argument generalizes at least in the sense that there can be no version of the safety condition that does justice to the considerations motivating a safety condition whilst, at the same time, being requisite for (...) knowledge. (shrink)