In logic and proof theory, natural deduction is a kind of proof calculus in which logical reasoning is expressed by inference rules closely related to the "natural" way of reasoning. This contrasts with the axiomatic systems which instead use axioms as much as possible to express the logical laws of deductive reasoning.
Read more about Natural Deduction: Motivation, Judgments and Propositions, Introduction and Elimination, Hypothetical Derivations, Consistency, Completeness, and Normal Forms, First and Higher-order Extensions, Proofs and Type-theory, Classical and Modal Logics
Famous quotes containing the word natural:
“The image cannot be dispossessed of a primordial freshness, which idea can never claim. An idea is derivative and tamed. The image is in the natural or wild state, and it has to be discovered there, not put there, obeying its own law and none of ours. We think we can lay hold of image and take it captive, but the docile captive is not the real image but only the idea, which is the image with its character beaten out of it.”
—John Crowe Ransom (1888–1974)