Christine Korsgaard sees normative generalizations as provisionally universal, in the sense that exceptions to them have reasons for being exceptions and that they could in principle be revised into more specific and precise absolutely universal rules. Do exceptions to normative generalizations have such explanations? Can such generalizations always be revised into or replaced by absolutely universal rules? The answer depends on the structure of practical space, and, specifically, the degree to which normative relations are definable. Distinguishing degrees of definability in (...) practical space opens up paths for generalist and particularist conceptions of normativity. (shrink)