 There is a second and equally important motivation for the position. It is almost unquestioned common ground in this field that there are two deeply different but parallel modes of rationality: theoretical and practical. Of these, philosophers tend to see inference about matters of fact as relatively unproblematic; to a first approximation, it is in order when you reliably derive truths from truths. Practical reasoning is seen as an analogous enterprise, one which is, however, much more opaque: because it determines what to do, as opposed to what to believe, it is much less clear when it is being executed correctly. Velleman’s move is to eliminate the commonly accepted distinction by reducing practical to theoretical rationality, and thereby reduce the problem of the correctness of practical inference to problems in the philosophy of explanation. 