The second major thesis of the book follows closely on the first: that the analysis of skeptical arguments is philosophically useful and important, and should therefore have a central role in the methodology of philosophy, and especially in the methodology of epistemology. A close analysis of skeptical arguments highlights our pre-theoretically plausible, but ultimately mistaken, assumptions about the nature of knowledge and evidence. Skeptical arguments are powerful just because their assumptions are so plausible pre-theoretically. But the arguments show us where (...) those assumptions lead, and thereby force us to rethink those assumptions. On this view, skeptical arguments constitute theoretical problems rather than practical problems. There is no “practical” or “existential” problem of skepticism. Rather, skeptical arguments show us that we need to rethink our assumptions about knowledge and evidence, and replace them with something better. (shrink)

This book, first published in 2000, is about the nature of skeptical arguments and their role in philosophical inquiry. John Greco delineates three main theses: that a number of historically prominent skeptical arguments make no obvious mistake, and therefore cannot be easily dismissed; that the analysis of skeptical arguments is philosophically useful and important, and should therefore have a central place in the methodology of philosophy; and that taking skeptical arguments seriously requires us to adopt an externalist, reliabilist epistemology. Greco (...) argues that the importance of skeptical arguments is methodological. It is further argued that taking skeptical arguments seriously requires us to adopt a version of 'virtue epistemology', or a theory of knowledge that makes intellectual virtue central in the analysis of knowledge. The above methodology has consequences for moral and religious epistemology; in particular, a theory of moral perception is defended. (shrink)

How much should your confidence in your beliefs be shaken when you learn that others – perhaps ‘epistemic peers’ who seem as well-qualified as you are – hold beliefs contrary to yours? This article describes motivations that push different philosophers towards opposite answers to this question. It identifies a key theoretical principle that divides current writers on the epistemology of disagreement. It then examines arguments bearing on that principle, and on the wider issue. It ends by describing some outstanding questions (...) that thinking about this issue raises. (shrink)

An argument that takes issue with the contemporary epistemological consensus that justification is distinct from knowledge, proposing instead that justified belief simply is knowledge, and arguing in detail that a belief is justified when ...

The aim of this paper is to sketch a theory of justified belief. What I have in mind is an explanatory theory, one that explains in a general way why certain beliefs are counted as justified and others as unjustified. Unlike some traditional approaches, I do not try to prescribe standards for justification that differ from, or improve upon, our ordinary standards. I merely try to explicate the ordinary standards, which are, I believe, quite different from those of many classical, (...) e. g., ‘Cartesian’, accounts. (shrink)

When we affirm that someone knows something, we are making a value judgment of sorts - we are claiming that there is something superior about that person's opinion, or their evidence, or perhaps about them. A central task of the theory of knowledge is to investigate the sort of evaluation at issue. This is the first book to make 'epistemic normativity,' or the normative dimension of knowledge and knowledge ascriptions, its central focus. John Greco argues that knowledge is a kind (...) of achievement, as opposed to mere lucky success. This locates knowledge within a broader, familiar normative domain. By reflecting on our thinking and practices in this domain, it is argued, we gain insight into what knowledge is and what kind of value it has for us. (shrink)

How much should your confidence in your beliefs be shaken when you learn that others – perhaps 'epistemic peers' who seem as well-qualified as you are – hold beliefs contrary to yours? This article describes motivations that push different philosophers towards opposite answers to this question. It identifies a key theoretical principle that divides current writers on the epistemology of disagreement. It then examines arguments bearing on that principle, and on the wider issue. It ends by describing some outstanding questions (...) that thinking about this issue raises. (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?

My conclusion will be that, more often than we might have thought, suspension of judgment is the epistemically proper attitude. It follows that in such cases we lack reasonable belief and so, at least on standard conceptions, knowledge. This is a kind of contingent real-world skepticism that has not received the attention it deserves. I hope that this paper will help to bring this issue to life.

Thomas Reid , the Scottish natural and moral philosopher, was one of the founding members of the Aberdeen Philosophical Society and a significant figure in the Scottish Enlightenment. Reid believed that common sense should form the foundation of all philosophical inquiry. He criticised the sceptical philosophy propagated by his fellow Scot David Hume and the Anglo-Irish bishop George Berkeley, who asserted that the external world did not exist outside the human mind. Reid was also critical of the theory of ideas (...) propagated by Locke and Descartes, arguing that it was incompatible with physical and experiential facts. For Reid, our senses demonstrate that the external world must exist, and this work is organised in chapters examining each of the senses in turn. The book, based on his lectures, was first published in 1764 when Reid was a regent professor at King's College, Aberdeen, and was reissued in 1818. (shrink)

Virtually all philosophers agree that for a belief to be epistemically justified, it must satisfy certain conditions. Perhaps it must be supported by evidence. Or perhaps it must be reliably formed. Or perhaps there are some other "good-making" features it must have. But does a belief's justification also require some sort of awareness of its good-making features? The answer to this question has been hotly contested in contemporary epistemology, creating a deep divide among its practitioners. Internalists, who tend to focus (...) on scientific or theoretical beliefs as the ideal, insist that such awareness is required for justification. Externalists, who think children's ordinary beliefs in obvious facts are paradigm cases of justified belief, say it isn't required. Michael Bergmann's book offers a decisive refutation of internalism and a sustained defense of externalism. (shrink)

The concept of evidence is among the central concerns of epistemology broadly construed. As such, it has long engaged the intellectual energies of both philosophers of science and epistemologists of a more traditional variety. Here I briefly survey some of the more important ideas to have emerged from this tradition of reflection. I then look somewhat more closely at an issue that has recently come to the fore, largely as a result of Williamson's Knowledge and Its Limits: that of whether (...) one's evidence supervenes on one's non-factive mental states. (shrink)

In this paper I shall closely examine some of Gilbert Harman's cases that purport to show that one can have a justified true belief that does not constitute knowledge because of the social environment. I shall provide an account of these cases that helps us not only understand why the people in these situations lack knowledge, but also why philosophers have a difficult time evaluating these cases. More specifically, I shall argue that in these cases we should conclude that the (...) cognizers lack justification. I shall also show how this account sheds some light on certain aspects of the internalism/externalism debate. (shrink)

This paper argues for externalism about justification on the basis of thought experiments. I present cases in which two individuals are intrinsically and introspectively indistinguishable and in which intuitively, one is justified in believing that p while the other is not. I also examine an argument for internalism based on the ideas that we have privileged access to whether or not our own beliefs are justified and that only internalism is compatible with this privilege. I isolate what I take to (...) be the most plausible form of privileged access to justification and show that it is compatible with externalism. (shrink)

Evidentialism is a view about the conditions under which a person is epistemically justified in having a particular doxastic attitude toward a proposition. Evidentialism holds that the justified attitudes are determined entirely by the person's evidence. This is the traditional view of justification. It is now widely opposed. The essays included in this volume develop and defend the tradition.Evidentialism has many assets. In addition to providing an intuitively plausible account of epistemic justification, it helps to resolve the problem of the (...) criterion, helps to disentangle epistemic and ethical evaluations, and illuminates the relationship between epistemic evaluations of beliefs and the evaluation of the methods used to form beliefs. These issues are all addressed in the essays presented here. External world skepticism poses the classic problem for an epistemological theory. The final essay in this volume argues that evidentialism is uniquely well qualified to make sense of skepticism and to respond to its challenge.Evidentialism is a version of epistemic internalism. Recent epistemology has included many attacks on internalism and has seen the development of numerous externalist theories. The essays included here respond to those attacks and raise objections to externalist theories, especially the principal rival, reliabilism. Internalism generally has been criticized for having unacceptable deontological implications, for failing to connect epistemic justification to truth, and for failing to provide an adequate account of what makes basic beliefs justified. Each of these charges is answered in these essays. The collection includes two previously unpublished essays and new afterwords to five of the reprinted essays; it will be the definitive resource on evidentialism for all epistemologists. (shrink)

My aim in this paper is to develop and defend a novel answer to a question that has recently generated a considerable amount of controversy. The question concerns the normative significance of peer disagreement. Suppose that you and I have been exposed to the same evidence and arguments that bear on some proposition: there is no relevant consideration which is available to you but not to me, or vice versa. For the sake of concreteness, we might picture.

Looking back on it, it seems almost incredible that so many equally educated, equally sincere compatriots and contemporaries, all drawing from the same limited stock of evidence, should have reached so many totally different conclusions---and always with complete certainty.

A rational person doesn’t believe just anything. There are limits on what it is rational to believe. How wide are these limits? That’s the main question that interests me here. But a secondary question immediately arises: What factors impose these limits? A first stab is to say that one’s evidence determines what it is epistemically permissible for one to believe. Many will claim that there are further, non-evidentiary factors relevant to the epistemic rationality of belief. I will be ignoring the (...) details of alternative answers in order to focus on the question of what kind of rational constraints one’s evidence puts on belief. Our main question concerns how far epistemic permission and obligation can come apart.1 Suppose I am epistemically permitted to believe P, i.e., it would not be irrational for me to believe it. Am I thereby obliged to believe P, or are other options rationally available to me?2 Might I be equally rational in remaining agnostic about P, or even believing not-P? Or could even a slightly stronger or weaker degree of confidence be just as reasonable? (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.

How should you take into account the opinions of an advisor? When you completely defer to the advisor's judgment, then you should treat the advisor as a guru. Roughly, that means you should believe what you expect she would believe, if supplied with your extra evidence. When the advisor is your own future self, the resulting principle amounts to a version of the Reflection Principle---a version amended to handle cases of information loss. When you count an advisor as an epistemic (...) peer, you should give her conclusions the same weight as your own. Denying that view---call it the ``equal weight view''---leads to absurdity: the absurdity that you could reasonably come to believe yourself to be an epistemic superior to an advisor simply by noting cases of disagreement with her, and taking it that she made most of the mistakes. Accepting the view seems to lead to another absurdity: that one should suspend judgment about everything that one's smart and well-informed friends disagree on, which means suspending judgment about almost everything interesting. But despite appearances, the equal weight view does not have this absurd consequence. Furthermore, the view can be generalized to handle cases involving not just epistemic peers, but also epistemic superiors and inferiors. (shrink)

How should one react when one has a belief, but knows that other people—who have roughly the same evidence as one has, and seem roughly as likely to react to it correctly—disagree? This paper argues that the disagreement of other competent inquirers often requires one to be much less confident in one’s opinions than one would otherwise be.

How does a particular experience evidence a particular perceptual belief for us? As Alvin Plantinga (Warrant and Proper Function, Oxford University Press, 1993, p. 98) puts it, "[W]hat makes it the case that a particular way of being appeared to--being appeared to greenly, say--is evidence for the proposition that I see something green?" Promising, but unsuccessful, answers cite a reliable connection between our having the experience and the belief's being true, our having good reason to believe in such a connection, (...) the proper functioning of our faculties, and objective epistemic norms. A superior view, developed here, is that our experience of being appeared to greenly evidences for us that something is green because we have learned to identify green objects by experiences of that sort. Our learning to do so amounts to our adopting an epistemic norm directing us to form that belief on the basis of that experience. (shrink)

This book presents an attempt to develop a theory of knowledge and a philosophy of mind using ideas derived from the mathematical theory of communication developed by Claude Shannon. Information is seen as an objective commodity defined by the dependency relations between distinct events. Knowledge is then analyzed as information caused belief. Perception is the delivery of information in analog form for conceptual utilization by cognitive mechanisms. The final chapters attempt to develop a theory of meaning by viewing meaning as (...) a certain kind of information-carrying role. (shrink)

Externalist analyses of justification typically include some sort of reliability requirement. But the fact that the beliefs of a demon victim can be justified despite their being formed in completely unreliable ways suggests that reliability isn’t required for justification. In this paper, I propose an analysis of justification in terms of proper function that enables us to hang on to the externalism without the reliability requirement. As an added bonus, the proposed analysis of justification yields an account of the elusive (...) connection between justification and truth. (shrink)

Change in View offers an entirely original approach to the philosophical study of reasoning by identifying principles of reasoning with principles for revising one's beliefs and intentions and not with principles of logic. This crucial observation leads to a number of important and interesting consequences that impinge on psychology and artificial intelligence as well as on various branches of philosophy, from epistemology to ethics and action theory. Gilbert Harman is Professor of Philosophy at Princeton University. A Bradford Book.

Toward theory a homuncular of believing For years and years, philosophers took thoughts and beliefs to be modifications of incorporeal Cartesian egos. ...

The concept of evidence is central to both epistemology and the philosophy of science. Of course, ‘evidence’ is hardly a philosopher's term of art: it is not only, or even primarily, philosophers who routinely speak of evidence, but also lawyers and judges, historians and scientists, investigative journalists and reporters, as well as the members of numerous other professions and ordinary folk in the course of everyday life. The concept of evidence would thus seem to be on firmer pre-theoretical ground than (...) various other concepts which enjoy similarly central standing within philosophy. (Contrast, for example, the epistemologist's quasi-technical term ‘epistemic justification’.). (shrink)

How does a particular experience evidence a particular perceptual belief for us? As Alvin Plantinga (Warrant and Proper Function, Oxford University Press, 1993, p. 98) puts it, “[W]hat makes it the case that a particular way of being appeared to—being appeared to greenly, say—is evidence for the proposition that 1 see something green?” Promising, but unsuccessful, answers cite a reliable connection between our having the experience and the belief's being true, our having good reason to believe in such a connection, (...) the proper functioning of our faculties, and objective epistemic norms. A superior view, developed here, is that our experience of being appeared to greenly evidences for us that something is green because we have learned to identify green objects by experiences of that sort. Our learning to do so amounts to our adopting an epistemic norm directing us to form that belief on the basis of that experience. (shrink)