The Source of Logical Necessity

Abstract This chapter presents an account of the source of logical necessity. An account according to which logical laws, and hence logical modality, have their source in thought, more particularly, in constitutive norms for thought, is introduced and defended. Constitutive norms for thought, it is explained, are norms evaluability in light of which is constitutive of thought. A test is introduced which, it is contended, all accounts of logical modality should pass. In short, any account of logical necessity must account for two important features: logical necessity is factive (if it is logically necessary that p, then p ); and some logical necessities are immune to rational doubt. It is argued that the proposed account of the source of logical modality passes the test, and that some rival accounts fail.