The Permissible Norm of Truth and “Ought Implies Can”

Many philosophers hold that a norm of truth governs the propositional attitude of belief. According to one popular construal of normativity, normativity is prescriptive in nature. The prescriptive norm can be formulated either in terms of obligation or permission: one ought to or may believe that p just in case p is true. It has been argued that the obligation norm is jointly incompatible with the maxim ought implies can and the assumption that there exists some truth that we cannot believe. The problem of the incompatible triad has motivated some to adopt the permissible norm of truth. I argue that the permissible norm faces an analogous problem of the incompatible triad.