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?

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.

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.

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.