Social epistemology

4. Collective knowledge

The key question of collective knowledge – of common, group and communal knowledge – is whether it reduces to individual knowledge or amounts to something over and above individual knowledge. A related question is whether individual knowledge must in some way be assimilated to communal knowledge (that is, the knowledge possessed by a community). The pragmatist C.S. Peirce argued for an affirmative answer to the latter question on the ground that the aim of proper method must be understood socially (see Peirce, C.S. §2). Peirce (1955) took the aim of proper method not to be true belief but relief from doubt. He then argued that the aim must be common rather than individual relief from doubt, since the ‘social impulse’ will drive people to think that others’ opinions are as good as their own, and thus differences of opinion will induce doubt. One might question whether it follows from the claim that relief from doubt depends psychologically on common relief from doubt, that the aim of proper method is common relief from doubt. But Peirce could reply that there is no point in taking relief from individual doubt as the aim when we will in any case have to aim at common belief. Clearly, Peirce’s argument for a common aim of proper method carries more weight for beliefs that are publicized, as in the case of science, than for beliefs that tend not to be exposed to the doubts of others (for example, beliefs about the details of one’s private life).

It is natural to think that Peirce’s argument, if successful, undermines a sharp distinction between individual and common knowledge, since a lone individual evidently cannot employ a method that aims at common beliefs; the coordinated efforts of many individuals are required. But whether Peirce’s argument goes this far depends on what a proper method involves. If it involves only accumulating the evidence that would suffice to dispel doubt, rather than including the social actions that actually dispel doubt, then an individual on their own may still employ a proper method.

There are other accounts of individual justification that in some way assimilate it to communal justification. In On Certainty, Wittgenstein suggests that an individual’s belief is justified by appeal to certain communally accepted claims. On a multi-perspectival view of justification, an individual is justified in believing p only if p is accepted from each perspective represented in the individual’s community. Another view is that a belief is justified only if it conforms to communally accepted rules (see Contextualism, epistemological).

Even if individual knowledge is not assimilated to communal knowledge, there remains the question of whether common or group knowledge stands over and above individual knowledge or, instead, reduces to it. Common or mutual knowledge does reduce to individual knowledge: it obtains when two or more individuals know a proposition, know that each of the others knows, and so on. Common knowledge has proved an essential ingredient in the analysis of social conventions and group knowledge, but whether it amounts to group knowledge is a matter of controversy.

The simplest individualistic account of group justification is a summative account: a group is justified in believing a proposition just in case most (or all) of its members are justified in believing the proposition. Opposed to an individualistic account is a joint account, on which group justification is not a matter of group members being justified in believing p, but of members jointly possessing a good reason to believe p, where members jointly possess a reason for p just in case they openly express a willingness to treat it as a reason for p. The joint account characterizes group justification in terms of the actions and attitudes of the group members. It thus avoids requiring for group justification that there be some group mind over and above the minds of the members of the group.