The literature on collective belief and collective intentionality has grown rapidly and is now quite extensive. Philosophers have applied the concepts of “collective belief” and “collective intentionality” in a variety of contexts, including political and legal contexts as well as scientific contexts, specifically to model the behavior of research teams and scientific specialties.

Gilbert (2000) examined the issue of collective intentionality in science. Her paper consisted of a conceptual analysis of the negative role of collective belief, consensus, and joint commitment in science, with a brief discussion of a case study investigated by Thagard (1998a, 1998b). I argue that Gilbert's concepts have to be refined to be empirically more relevant. Specifically, I distinguish between different kinds of joint commitments. I base my analysis on a close examination of Thagard's example, the discovery of Helicobacter pylori, and two other historical cases involving the Copenhagen school of quantum mechanics and the Austrian school of economics. I also argue that it is difficult to fulfill the condition of common knowledge, even in Gilbert's weak sense. I conclude by raising serious doubts about the very possibility of a certain type of joint commitment, which I refer to as an implicit joint commitment.

There can be good reasons to doubt the authority of a group of scientists. But those reasons do not include lack of unanimity among them. Indeed, holding science to a unanimity or near-unanimity standard has a pernicious effect on scientific deliberation, and on the transparency that is so crucial to the authority of science in a democracy. What authorizes a conclusion is the quality of the deliberation that produced it, which is enhanced by the presence of a non-dismissible minority. Scientists can speak as one in more ways than one. We recommend a different sort of consensus that is partly substantive and partly procedural. It is a version of what Margaret Gilbert calls “joint acceptance”–we call it “deliberative acceptance.” It capitalizes on there being a persistent minority, and thereby encourages accurate reporting of the state of agreement and disagreement among deliberators.

An analysis of group justification enables us to understand what it means to say that a research group is justified in making a claim on the basis of evidence. I defend Frederick Schmitt's (1994) joint account of group justification by arguing against a simple summative account of group justification. Also, I respond to two objections to the joint account, one claiming that social epistemologists should always prefer the epistemic value of making true judgments to the epistemic value of maintaining consistency, and another one claiming that the notion of joint commitment implicit in the joint account is epistemically unacceptable.

Some prominent accounts of scientific evidence treat evidence as an unrelativized concept. But whether belief in a hypothesis is justified seems relative to the epistemic situation of the believer. The issue becomes yet more complicated in the context of group epistemic agents, for then one confronts the problem of relativizing to an epistemic situation that may include conflicting beliefs. As a step toward resolution of these difficulties, an ideal of justification is here proposed that incorporates both an unrelativized evidence requirement and the requirement of the security of the evidence on which a conclusion from data is based. The latter requirement incorporates the consideration of epistemic modal statements.

Recently, several scholars have argued that scientists can accept scientific claims in a collective process, and that the capacity of scientific groups to form joint acceptances is linked to a functional division of labor between the group members. However, these accounts reveal little about how the cognitive content of the jointly accepted claim is formed, and how group members depend on each other in this process. In this paper, I shall therefore argue that we need to link analyses of joint acceptance with analyses of distributed cognition. To sketch how this can be done, I shall present a detailed case study, and on the basis of the case, analyze the process through which a group of scientists jointly accept a new scientific claim and at a later stage jointly accept to revise previously accepted claims. I shall argue that joint acceptance in science can be established in situations where an overall conceptual structure is jointly accepted by a group of scientists while detailed parts of it are distributed among group members with different areas of expertise, a condition that I shall call a heterogeneous conceptual consensus. Finally, I shall show how a heterogeneous conceptual consensus can work as a constraint against scientific change and address the question how changes may nevertheless occur.

This paper uses the economic crisis of 2008 as a case study to examine the explanatory validity of collective mental representations. Distinguished economists such as Paul Krugman and Joseph Stiglitz attribute collective beliefs, desires, intentions, and emotions to organizations such as banks and governments. I argue that the most plausible interpretation of these attributions is that they are metaphorical pointers to a complex of multilevel social, psychological, and neural mechanisms. This interpretation also applies to collective knowledge in science: scientific communities do not literally have collective representations, but social mechanisms do make important contributions to scientific knowledge.