Deductive reasoning Deductive closure Deductive language Hypothetico-deductive model Deductive database Deductive pragmatism Deductive mood Formal system Deductive-nomological model Theory (mathematical logic) Metalogic Legal syllogism Inductive reasoning Formal fallacy Deductive classifier Hilbert system Natural deduction Corollary Deduction theorem Completeness (logic) First-order logic Principle of explosion Mathematical model Causal reasoning Lambda calculus