There have recently been a series of prominent projects in the UK that aim to bring philosophy into the heart of prison education. The aim of this paper is to consider a possible rationale for this pedagogical development. A distinction is drawn between a content and a sensibility approach to teaching philosophy, where the latter is primarily concerned not with teaching a particular subject matter but rather with developing a certain kind of critical expertise. It is argued that the sensibility conception of teaching philosophy dovetails with an influential account of the epistemic aim of education in terms of the cultivation of intellectual character, in the specific sense of developing the intellectual virtues that constitute one's intellectual character (i.e., virtuous intellectual character). The significance of this point for prison education is illustrated by considering how the use of a pedagogical approach in prison education known as CoPI ('Community of Philosophical Inquiry') can be construed as teaching philosophy on the sensibility model just outlined. With this in mind, it is argued that the value of teaching philosophy in prisons primarily relates to how it provides a particularly fundamental kind of education, one that is both finally and instrumentally valuable. These points are illustrated throughout by considering a particular case study involving a recent philosophy in prisons project that employed the CoPI methodology.