Epistemic systems are social processes generating judgments of truth and falsity. I outline a mathematical theory of epistemic systems that applies widely. Areas of application include pure science, torture, police forensics, espionage, auditing, clinical medical testing, democratic procedure, and the market economy. I examine torture and police forensics in relative detail. This paper is an exercise in comparative institutional epistemics, which considers how the institutions of an epistemic system influence its performance as measured by such things as error rates and the volume of judgments generated.

Openness is one of the most important principles in scientific inquiry, but there are many good reasons for maintaining secrecy in research, ranging from the desire to protect priority, credit, and intellectual property, to the need to safeguard the privacy of research participants or minimize threats to national or international security. This article examines the clash between openness and secrecy in science in light of some recent developments in information technology, business, and politics, and makes some practical suggestions for resolving conflicts between openness and secrecy.

As sources of knowledge, perception and testimony are both vulnerable to sceptical arguments. To both arguments a Moorean response is possible: both can be refuted by reference to particular things known by perception and testimony. However, lies and dreams are different possibilities and they are different in a way that undercuts the plausibility of a Moorean response to a scepticism of testimony. The condition placed on testimonial knowledge cannot be trivially satisfied in the way the Moorean would suggest. This has substantial implications for any non-sceptical epistemological theory of testimony.

Contemporary liberal democracy employs a conception of legitimacy according to which political decisions and institutions must be at least in principle justifiable to all citizens. This conception of legitimacy is difficult to satisfy when citizens are deeply divided at the level of fundamental moral, religious, and philosophical commitments. Many have followed the later Rawls in holding that where a reasonable pluralism of such commitments persists, political justification must eschew appeal to any controversial moral, religious, or philosophical premises. In this way, the Rawlsian account of public political justification involves a politics of omission, where citizens are expected to bracket off their most fundamental commitments and seek justifications that draw only from uncontroversial premises. This politics of omission is necessary, Rawls argues, for political stability. But there is good social epistemic evidence for the view that the politics of omission encourages insularity among like-minded groups, and that this insularity in turn generates extremism. So omission is likely to lead to instability, not stability.

All of us get opinions from other people. And not just a few. We acquire opinions from others extensively and do so from early childhood through virtually every day of the rest our lives. Sometimes we rely on others for relatively inconsequential information. Is it raining outside? Did the Yankees win today? But we also depend on others for important or even life preserving information. Where is the nearest hospital? Do people drive on the left or the right here? We acquire opinions from family and close acquaintances but also from strangers. We get directions from and heed the warnings of individuals we've never met, and likewise read books and articles and listen to television and radio reports authored by individuals we don't know personally. Moreover, we undertake inquiries in groups in which the group relies on the conclusions of the individuals making up the group. In some of these collective efforts everyone knows one another, for example, a set of neighbors taking a census of birds in the neighborhood. But others, such as the effort to understand gravity, are not so nearly self-contained. Indeed, many of the most impressive human intellectual accomplishments are the collective products of individuals far removed from another in location (and sometimes even over time) who rely on each other's conclusions without feeling the need to re-confirm them.

Andy believes that p because his tarot cards indicate that p. Betty believes that ∼p because her crystal ball reveals that ∼p. If Andy and Betty know that they disagree, and disagree because they engage in different practices, is Andy's belief that p rational? The answer depends in part on whether Andy has good reasons to think that reading tarot cards is reliable about the topic while reading crystal balls is not. If a person has good reasons to believe that practice P1 is reliable while a competing practice P2 is not, then it is not irrational to form beliefs by engaging in P1. What if a person does not have good reasons to think that one practice is reliable about a topic while competing practices are not, though? In such cases, would Andy's awareness of the existence of competing practices, on its own, be enough to render his belief that p irrational?

The Ostrogorski paradox and the discursive dilemma are seemingly unrelated paradoxes of aggregation. The former is discussed in traditional social choice theory, while the latter is at the core of the new literature on judgment aggregation. Both paradoxes arise when, in a group, each individual consistently makes a judgment, or expresses a preference, (in the form of yes or no) over specific propositions, and the collective outcome is in some respect inconsistent. While the result is logically inconsistent in the case of the discursive paradox, it is not stable with respect to the level of aggregation in the case of the Ostrogorski paradox. In the following I argue that, despite these differences, the two problems have a similar structure. My conclusion will be twofold: on the one hand, the similarities between the paradoxes support the claim that these problems should be tackled using the same aggregation procedure; on the other hand, applying the same procedure to these paradoxes will help clarify the strengths and weaknesses of the aggregation method itself. More specifically, I will show that an operator defined in artificial intelligence to merge belief bases can deal with both paradoxes.

Recently, there has been a debate focusing on the question of whether groups can literally have beliefs. For the purposes of epistemology, however, the key question is whether groups can have knowledge. More specifically, the question is whether “group views” can have the key epistemic features of belief, viz., aiming at truth and being epistemically rational. I argue that, while groups may not have beliefs in the full sense of the word, group views can have these key epistemic features of belief. However, I argue that on Margaret Gilbert's influential “plural subject” account of group belief, group views are unlikely to be epistemically rational.

Most epistemologists of testimony assume that testifying requires that the beliefs to which speakers attest are identical to the beliefs that hearers accept. I argue that this characterization of testimony is misleading. Characterizing testimony in terms of duplicating speaker/hearer belief unduly resticts the variety of beliefs that might be accepted from speaker testimony.

In order to guide the decisions of real people who want to bring about good epistemic outcomes for themselves and others, we need to understand our epistemic values. In Knowledge in a Social World, Alvin Goldman has proposed an epistemic value theory that allows us to say whether one outcome is epistemically better than another. However, it has been suggested that Goldman's theory is not really an epistemic value theory at all because whether one outcome is epistemically better than another partly depends on our non-epistemic interests. In this paper, I argue that an epistemic value theory that serves the purposes of social epistemology must incorporate non-epistemic interests in much the way that Goldman's theory does. In fact, I argue that Goldman's theory does not go far enough in this direction. In particular, the epistemic value of having a particular true belief should actually be weighted by how interested we are in the topic.

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.

Scientific research is reconstructed as a language game along the lines of Robert Brandom's inferentialism. Researchers are assumed to aim at persuading their colleagues of the validity of some claims. The assertions each scientist is allowed or committed to make depend on her previous claims and on the inferential norms of her research community. A classification of the most relevant types of inferential rules governing such a game is offered, and some ways in which this inferentialist approach can be used for assessing scientific knowledge and practices are explored. Some similarities and differences with a game-theoretic analysis are discussed.

We frequently make judgments about the world. Juries make judgments about whether defendants are guilty. Umpires make judgments about whether pitches are strikes. Tenure committees make judgments about whether professors deserve tenure. We typically want these judgments about the world to have good epistemic properties. We would like our judgments to be true rather than false, for example. We would also like our judgments to be consistent with each other; and we would like to have good reasons for our judgments. This paper will be concerned with how we can make judgments that have such good epistemic properties.

Discussions of conservatism in epistemology often fail to demonstrate that the principle of conservatism is supported by epistemic considerations. In this paper, I hope to show two things. First, there is a defensible version of the principle of conservatism, a version that applies only to what I will call our basic beliefs. Those who deny that conservatism is supported by epistemic considerations do so because they fail to take into account the necessarily social, diachronic and self-correcting nature of our epistemic practice. Second, I will attempt to show how our basic beliefs are justified via this principle of conservatism.

From time to time, philosophers like to raise the possibility of the existence of group minds or group persons. In order for something to be interestingly and appropriately described as a group person it must satisfy two conditions. First, it must itself exhibit various characteristics that are distinctive of persons. Unless it did this, it would not be a group person. Secondly, it must be composed of entities that are themselves persons or relevantly person-like. Without this, it would not be a group person. It is the difficulty of seeing how these two conditions can be satisfied together that has made the existence and possible natures of group persons problematic. For the things that paradigmatically satisfy the first condition, namely persons, are not obviously thought of as being composed of person-like entities related in some group-like way. And the things that paradigmatically satisfy the second condition, such as sports teams, committees and string quartets, are not obviously thought of as themselves displaying personal characteristics. Investigators of group persons – though not always thinking of themselves as such – have usually approached the problem by starting with paradigmatic and uncontroversial groups and exploring the extent to which personal characteristics can be attributed to them. Since it would be unreasonable to expect such groups to exhibit, even in some possibly attenuated way, all the characteristics of an ordinary person, attention is usually directed to some subset of these characteristics. Can such a group have a single consciousness? Can it be the subject of intentional mental states like belief? Can it act? Can it be guilty?

Social epistemology is autonomous: When applied to the same evidential situations, the principles of social rationality and the principles of individual rationality sometimes recommend inconsistent beliefs. If we stipulate that reasoning rationally from justified beliefs to a true belief is normally sufficient for knowledge, the autonomy thesis implies that some knowledge is essentially social. When the principles of social and individual rationality are applied to justified evidence and recommend inconsistent beliefs and the belief endorsed by social rationality is true, then that true belief would be an instance of social knowledge but not individual knowledge.

Rationality and reason are topics so fraught for feminists that any useful reflection on them requires some prior exploration of the difficulties they have caused. One of those difficulties for feminists and, I suspect, for others in the margins of modernity, is the rhetoric of reason – the ways reason is bandied about as a qualification differentially bestowed on different types of person. Rhetorically, it functions in different ways depending on whether it is being denied or affirmed. In this paper, I want to explore these rhetorics of reason as they are considered in the work of two feminist philosophers. I shall draw on their work for some suggestions about how to think about rationality, and begin to use those suggestions to develop a constructive account that withstands the rhetorical temptations.