Natural Deduction

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:

    Men speak of natural rights, but I challenge any one to show where in nature any rights existed or were recognized until there was established for their declaration and protection a duly promulgated body of corresponding laws.
    Calvin Coolidge (1872–1933)