 Idealization limits the set of reasons that figure into public justification. “Normative” idealizations that represent the public as reasonable do likewise. In one way, reasonableness may seem to be a redundant category. Rawls, Gauthier, and Habermas represent citizens as reasonable by depriving them of partializing information. But reasonableness is not redundant. It attributes cognitive dispositions to agents uncaptured by idealizing beliefs, desires, and values.