Groups can be epistemically vicious just like individuals. And just like individuals, groups sometimes want to do something about their vices. They want to change. However, intentionally combating one’s own vices seems impossible without detecting those vices first. Self-knowledge seems to provide a first step towards changing one’s own epistemic vices. I argue that groups can acquire self-knowledge about their epistemic vices and I propose an account of such collective self-knowledge. I suggest that collective self-knowledge of vices is partially based (...) on evidence that a group can generate by performing internal promptings. Whereas these promptings are done mentally in individual self-knowledge, these promptings are done by interactions of group members in the collective case. The group can then acquire inferential self-knowledge of their vices based on the evidence generated by the interactions within the group. Groups thereby bring themselves into a position from which they can combat and change those vices intentionally. (shrink)