In discussions of social epistemology, Jennifer Lackey (2021) argues that ‘a significant percentage of a group’s operative members who believe that p’ is a necessary condition for ‘a group believes that p.’ Meanwhile, with respect to group evidence, she maintains that, in certain cases, evidence possessed by a minority of members can constitute group evidence. However, in ordinary thought, there is an intuition about evidence according to which only propositions that a subject takes to be true can serve as that subject’s evidence. This intuition is also widely endorsed in philosophical discussions of evidence by scholars such as Jessica Brown (2022). In response, this paper formulates a requirement on evidence based on this intuition and uses it to argue that Jennifer Lackey’s position in social epistemology is internally inconsistent.
