We carry out most of our epistemic projects as groups. Networks of individuals work together to identify questions, accumulate evidence, and settle on answers that lie beyond the ken of individual knowers. This is particularly important for controversial issues. And when it comes to ideologically contested issues, groups that are ideologically diverse in their membership are epistemically superior to groups that are ideologically homogenous. That’s because ideologically diverse groups are better at (a) identifying a representative sample of important questions, (b) (...) developing a wider range of potential answers, and (c) evaluating the evidence for and against each option. Awareness of this point produces a competence defeater for the relevant outputs of ideologically homogenous groups: they don’t deserve the high level of trust we often grant them. That, among other things, goes a long way towards justifying the public’s decreased trust in institutions like social networks, journalism, and universities. (shrink)