Extending the Space of Reasons: Comments on Chapter Four of Understanding People

Wilfrid Sellars employs the metaphor of the space of reasons to express a certain conception of knowledge: “in characterising an episode or state as that of knowing … one is placing it in the logical space of reasons, of justifying and being able to justify what one says”.1 A growing number of philosophers employ the same metaphor to express a conception of at least some (other) mental states: in characterising a state as that of belief, or intention, one is placing it in the same logical space.2 The burden of Alan Millar’s characteristically careful and thought-provoking book is to tell us what this conception amounts to, and to argue for its truth. Its central claim is that the concepts of belief and intention, and what they are concepts of, are (in a sense to be explained) normative. Chapter four – “the heart of the book”, in Millar’s view3 – is devoted to explaining, and defending this claim