Closed-mindedness is a characteristic trait of irresponsible believers. For this reason and others, educators should actively discourage closed-mindedness in their students. One way to do this is to cultivate its opposing virtue: open-mindedness. Drawing on the work of William Hare, Danielle Diver defends the status of open-mindedness as an epistemic virtue and explains why it is truth-conducive, even in epistemically hostile environments. Diver goes on to argue that open-mindedness is fundamental to the practice of philosophy and that teaching philosophy in schools, especially through the methods of Philosophy for Children (P4C), is an effective way to cultivate open-mindedness in students. Teaching philosophy therefore has a valuable role to play in the education of responsible believers.