This paper argues that practical reasons are essentially “public” in the following sense: If R is a reason for X to Φ, then R is also a reason for other people not to interfere with X’s Φ-ing. The paper derives the Publicity Thesis from an independently motivated non-cognitivist account of normative judgment that covers both should-judgments and judgments about reasons. This account “explains” the publicity thesis in the sense if the non-cognitivist view is correct, anyone who judges that R is (...) a reason for X to Φ is thereby committed to regarding R as a reason for others not to interfere. Hence practical reasons must be regarded as public by anyone who thinks about them, and so are essentially public, though in a sense somewhat different from Korsgaard’s (1996) or Nagel’s (1970). -/- . (shrink)