What makes the difference between good and bad reasoning? In this paper we defend a novel account of good reasoning—both theoretical and practical—according to which it preserves fittingness or correctness: good reasoning is reasoning which is such as to take you from fitting attitudes to further fitting attitudes, other things equal. This account, we argue, is preferable to two others that feature in the recent literature. The first, which has been made prominent by John Broome, holds that the standards of good reasoning derive from rational requirements. The second holds that these standards derive from reasons. We argue that these accounts face serious difficulties in correctly distinguishing good from bad reasoning, and in explaining wh...