What role, if any, does formal logic play in characterizing epistemically rational belief? Traditionally, belief is seen in a binary way - either one believes a proposition, or one doesn't. Given this picture, it is attractive to impose certain deductive constraints on rational belief: that one's beliefs be logically consistent, and that one believe the logical consequences of one's beliefs. A less popular picture sees belief as a graded phenomenon.

Judgment aggregation studies how collective opinions arise from the aggregation of individual ones. This article surveys a variety of aggregation rules (possible ways of aggregating individual judgments into collective ones). Aggregation by majority opinion is known to satisfy some but not all the desiderata for an aggregation rule. More general impossibility results show that not all the natural desiderata can be satisfied by a single aggregation rule. To interpret these results, we focus here on some applications of judgment aggregation models (...) in Epistemology. In particular, we explore their possible role in an account of collective belief and collective reason. The focus on these applications allows us to give precise answers concerning which of the natural desiderata must be abandoned. (shrink)

Judgment aggregation is naturally applied to the modeling of collective attitudes. In the individual case, we represent agents as having not just beliefs, but also as supporting them with reasons. Can the Judgment Aggregation help model a concept of collective reason? I argue that the resources of the standard judgment aggregation framework are insufficiently general. I develop a generalization of the framework that improves along this dimension. In the new framework, new aggregation rules become available, as well as a natural (...) account of collective reasons. (shrink)

1 Knowledge and Justification This book is an investigation of one central problem which arises in the attempt to give a philosophical account of empirical ...

There is a social or collective sense of ‘knowledge’, as used, for example, in the phrase ‘the growth of scientific knowledge’. In this paper I show that social knowledge does not supervene on facts about what individuals know, nor even what they believe or intend, or any combination of these or other mental states. Instead I develop the idea that social knowing is an analogue to individual knowing, where the analogy focuses on the functional role of social and individual knowing.

Despite various attempts to rectify matters, the internalism-externalism (I-E) debate in epistemology remains mired in serious confusion. I present a new account of this debate, one which fits well with entrenched views on the I-E distinction and illuminates the fundamental disagreements at the heart of the debate. Roughly speaking, the I-E debate is over whether or not certain of the necessary conditions of positive epistemic status are internal. But what is the sense of internal here? And of which conditions of (...) which positive epistemic status are we speaking? I argue that an adequate answer to these questions requires reference to what I call the no-defeater condition which is satisfied by a subjects belief B just in case she does not believe that B is defeated. I close by stating succinctly the main positions taken in the I-E debate, identifying the basic points of disagreement and suggesting fruitful courses for future discussion. (shrink)

Jason Stanley presents a startling and provocative claim about knowledge: that whether or not someone knows a proposition at a given time is in part determined by his or her practical interests, i.e. by how much is at stake for that person at that time. In defending this thesis, Stanley introduces readers to a number of strategies for resolving philosophical paradox, making the book essential not just for specialists in epistemology but for all philosophers interested in philosophical methodology. Since a (...) number of his strategies appeal to linguistic evidence, it will be of great interest to linguists as well. (shrink)

In this companion volume to Warrant: The Current Debate, Plantinga develops an original approach to the question of epistemic warrant; that is what turns true belief into knowledge. He argues that what is crucial to warrant is the proper functioning of one's cognitive faculties in the right kind of cognitive environment.

By means of an example, shows the possibility of beliefs that are separately rational whilst together inconsistent.

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)

This new edition of the classic Contemporary Theories of Knowledge has been significantly updated to include analyses of the recent literature in epistemology.

Inspired by the work of Wilfrid Sellars, Michael Williams launches an all-out attack on what he calls "phenomenalism," the idea that our knowledge of the world rests on a perceptual or experiential foundation.

§I schematises the evidence for an understanding of ‘know’ and other terms of epistemic appraisal that embodies contextualism or subject-sensitive invariantism, and distinguishes between those two approaches. §II argues that although the cases for contextualism and sensitive invariantism rely on a principle of charity in the interpretation of epistemic claims, neither approach satisfies charity fully, since both attribute metalinguistic errors to speakers. §III provides an equally charitable anti-sceptical insensitive invariantist explanation of much of the same evidence as the result of (...) psychological bias caused by salience effects. §IV suggests that the explanation appears to have implausible consequences about practical reasoning, but also that applications of contextualism or sensitive invariantism to the problem of scepticism have such consequences. §V argues that the inevitable difference between appropriateness and knowledge of appropriateness in practical reasoning, closely related to the difference between knowledge and knowledge of knowledge, explains the apparent implausibility. (shrink)

It is argued in this paper that there can be both normative and nonnormative, merely factual group beliefs. The former involve the whole social group in question, while the latter only relate to the distributions of personal beliefs within the group. The paper develops a detailed theory, called the positional account of group beliefs, to explicate normative, group-involving group beliefs. Normative group beliefs are characterized within this approach in terms of joint acceptances of views by the group members — or (...) their representatives — acting in their right positions and tasks, and in a sense creating group commitments for all the members to accept (and keep accepting) the view in question. Also aggregate accounts of group belief are considered in the paper, especially the shared we-belief approach. Such aggregate accounts purport to account for merely factual group beliefs. (shrink)

The main task of the present paper is to investigate the nature of collective knowledge and discuss what kind of justificatory aspects are involved in it to discuss it from collective belief. The central kind of collective knowledge investigated is normatively binding knowledge attributed to a social group. A distinction is made between natural knowledge and constitutive knowledge related to social (especially institutional) matters. In the case of the latter kind of knowledge, in contrast to the former kind, justification and (...) the criteria of justification are purely social. Knowledge is regarded as a primitive, irreducible notion that accordingly does not fall prey to Gettier-type paradoxes. (shrink)

In “Group Testimony” (2007) I argued that the testimony of a group cannot be understood (or at least cannot always be understood) in a summative fashion; as the testimony of some or all of the group members. In some cases, it is the group itself that testifies. I also argued that one could extend standard reductionist accounts of the justification of testimonial belief to the case of testimonial belief formed on the basis of group testimony. In this paper, I explore (...) the issue of group testimony in greater detail by focusing on one putative source of testimony, that of Wikipedia. My aim is to the answer the following questions: Is Wikipedia a source of testimony? And if so, what is the nature of that source? Are we to understand Wikipedia entries as a collection of testimonial statements made by individuals, some subset of individuals, or is Wikipedia itself (the organization or the Wikipedia community) the entity that testifies? If Wikipedia itself is a source of testimony, what resources do we have for assessing the trustworthiness of such an unusual epistemic source? In answering these questions I hope to further elucidate the nature of collective epistemic agency (Tollefsen 2006), of which group testimony is a paradigm example. When a mans Discourse begineth…at some saying of another, of whose ability to know the truth, and of whose honesty in not deceiving, he doubteth not; and then the Discourse is not so much concerning the Thing, as the Person; and the Resolution is called Beleefe, and Faith: Faith in the man. (1651/1991, Ch. 7; p. 48). (shrink)

The fact that much of our knowledge is gained through the testimony of others challenges a certain form of epistemic individualism. We are clearly not autonomous knowers. But the discussion surrounding testimony has maintained a commitment to what I have elsewhere called epistemic agent individualism. Both the reductionist and the anti-reductionist have focused their attention on the testimony of individuals. But groups, too, are sources of testimony - or so I shall argue. If groups can be testifiers, a natural question (...) to ask is whether our beliefs based on the testimony of groups are ever justified and whether such a justification is to be conferred inferentially or non-inferentially. I consider and dismiss the possibility of extending an anti-reductionist account of justification to our group testimonial beliefs. I also argue against a version of reductionism that would have our group testimonial beliefs justified only in so far as we were able to monitor the trustworthiness of members of the group. However, there are forms of reductionism that can be extended to make sense of the justification of our group testimonial beliefs. There are mechanisms for monitoring the trustworthiness and competency of a group (rather than its members) and, further, a variety of background beliefs allow us to assess the testimony of a group for reliability. (shrink)

Jason Stanley's "Knowledge and Practical Interests" is a brilliant book, combining insights about knowledge with a careful examination of how recent views in epistemology fit with the best of recent linguistic semantics. Although I am largely convinced by Stanley's objections to epistemic contextualism, I will try in what follows to formulate a version that might have some prospect of escaping his powerful critique.

It is generally assumed that there are (at least) two fundamental epistemic goals: believing truths, and avoiding the acceptance of falsehoods. As has been often noted, these goals are in conflict with one another. Moreover, the norms governing rational belief that we should derive from these two goals depend on how we weight them relative to one another. However, it is not obvious that there is one objectively correct weighting for everyone in all circumstances. Indeed, as I shall argue, it (...) looks as though there are circumstances in which a range of possible weightings of the two goals are all equally epistemically rational. (shrink)

Epistemic circularity occurs when a subject forms the belief that a faculty F is reliable through the use of F. Although this is often thought to be vicious, externalist theories generally don't rule it out. For some philosophers, this is a reason to reject externalism. However, Michael Bergmann defends externalism by drawing on the tradition of common sense in two ways. First, he concedes that epistemically circular beliefs cannot answer a subject's doubts about her cognitive faculties. But, he argues, subjects (...) don't have such doubts, so epistemically circular beliefs are rarely called upon to play this role. Second, following Thomas Reid, Bergmann argues that we have noninferential, though epistemically circular, knowledge that our faculties are reliable. I argue, however, that Bergmann's view is undermined by doubts a subject should have and that there is no plausible explanation for how we can have noninferential knowledge that our faculties are reliable. (shrink)

Logical puzzles like the doctrinal paradox raise the problem of how to aggregate individual judgements into a collective judgement, or alternatively, how to merge collectively inconsistent knowledge bases. In this paper, we view judgement aggregation as a function on propositional logic valuations, and we investigate how logic constrains judgement aggregation. In particular, we show that there is no non-dictatorial decision method for aggregating sets of judgements in a logically consistent way if the decision method is local, i.e., only depends on (...) the individual judgements on the proposition under consideration. (shrink)

Logical puzzles like the doctrinal paradox raise the problem of how to aggregate individual judgements into a collective judgement, or alternatively, how to merge collectively inconsistent knowledge bases. In this paper, we view judgement aggregation as a function on propositional logic valuations, and we investigate how logic constrains judgement aggregation. In particular, we show that there is no non-dictatorial decision method for aggregating sets of judgements in a logically consistent way if the decision method is local, i.e., only depends on (...) the individual judgements on the proposition under consideration. (shrink)

This paper gives an account of proxy agency in the context of collective action. It takes the case of a group announcing something by way of a spokesperson as an illustration. In proxy agency, it seems that one person or subgroup's doing something counts as or constitutes or is recognized as (tantamount to) another person or group's doing something. Proxy agency is pervasive in institutional action. It has been taken to be a straightforward counterexample to an appealing deflationary view of (...) collective action as a matter of all members of a group making a contribution to bringing about some event. I show that this is a mistake. I give a deflationary account of constitutive rules in terms of essentially collective action types. I then give an account of one form of constitutive agency in terms of constitutive rules. I next give an account of status functions—of which being a spokesperson is one—that also draws on the concept of a constitutive rule. I then show how these materials help us to see how proxy agency is an expression of the agency of all members of the group credited with doing something when the proxy acts. (shrink)

In this paper, I introduce the emerging theory of judgment aggregation as a framework for studying institutional design in social epistemology. When a group or collective organization is given an epistemic task, its performance may depend on its ‘aggregation procedure’, i.e. its mechanism for aggregating the group members’ individual beliefs or judgments into corresponding collective beliefs or judgments endorsed by the group as a whole. I argue that a group’s aggregation procedure plays an important role in determining whether the group (...) can meet two challenges: the ‘rationality challenge’ and the ‘knowledge challenge’. The rationality challenge arises when a group is required to endorse consistent beliefs or judgments; the knowledge challenge arises when the group’s beliefs or judgments are required to track certain truths. My discussion seeks to identify those properties of an aggregation procedure that affect a group’s success at meeting each of the two challenges. (shrink)

Suppose that the members of a group each hold a rational set of judgments on some interconnected questions, and imagine that the group itself has to form a collective, rational set of judgments on those questions. How should it go about dealing with this task? We argue that the question raised is subject to a difficulty that has recently been noticed in discussion of the doctrinal paradox in jurisprudence. And we show that there is a general impossibility theorem that that (...) difficulty illustrates. Our paper describes this impossibility result and provides an exploration of its significance. The result naturally invites comparison with Kenneth Arrow's famous theorem (Arrow, 1963 and 1984; Sen, 1970) and we elaborate that comparison in a companion paper (List and Pettit, 2002). The paper is in four sections. The first section documents the need for various groups to aggregate its members' judgments; the second presents the discursive paradox; the third gives an informal statement of the more general impossibility result; the formal proof is presented in an appendix. The fourth section, finally, discusses some escape routes from that impossibility. (shrink)

Several authors have recently contended that modern statistical theory provides a powerful argument in favor of the view that if scientists accept or reject hypotheses at all they do so only in a behavioral sense--i.e., in a sense which reduces "accepting P" to "acting on the basis of P relative to an objective O". In this paper, the argument from statistics in favor of a behavioral view is outlined; an interpretation of two statistical procedures (Bayes method and signifigance testing) is (...) offered which does not entail a behavioral analysis of "accepting a hypothesis"; and the conclusion that non-behavioral analyses of belief are compatible with the application of current statistical theory in the sciences is tentatively advanced. (shrink)

Recently, much attention has been paid to ‘rational requirements’ and, especially, to what I call ‘rational requirements of formal coherence as such’. These requirements are satisfied just when our attitudes are formally coherent: for example, when our beliefs do not contradict each other. Nevertheless, these requirements are puzzling. In particular, it is unclear why we should satisfy them. In light of this, I explore the conjecture that there are no requirements of formal coherence. I do so by trying to construct (...) a theory of error for the idea that there are such requirements. (shrink)

I "argue" that by knowingly accepting a set of propositions which is logically inconsistent, An epistemic agent need not violate any valid epistemic rule. Those types of logically inconsistent sets which it is permissible to accept are distinguished from those which may not be accepted. The results of the discussion are applied to the lottery paradox set of propositions and the preface paradox set. I also "suggest" that it may be an epistemic virtue to accept some inconsistent sets.

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)

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)