Explore: Contradiction (logic)

In traditional logic, a contradiction involves a proposition conflicting either with itself or established fact. It is often used as a tool to detect disingenuous

In logic, proof by contradiction is a form of proof that establishes the truth or the validity of a proposition by showing that assuming the proposition

traditional systems of logic (e.g., classical logic and intuitionistic logic), every statement becomes a theorem if a contradiction is true, trivialising

In logic, the law of noncontradiction (LNC; also known as the law of contradiction, principle of non-contradiction (PNC), or the principle of contradiction)

classical logic (as well as intuitionistic logic and most other logics), contradictions entail everything. This feature, known as the principle of explosion

In mathematical logic, a tautology (from Ancient Greek: ταυτολογία) is a formula that is true regardless of the interpretation of its component terms

contradiction. Assume that "this sentence is false" is true, then we can trust its content, which states the opposite and thus causes a contradiction

claim by showing that following the logic of a proposition or argument would lead to absurdity or contradiction. This argument form traces back to Ancient

proofs are allowed (like the classic proof by contradiction without a witness). The main constructive logics are the following: Founder: L. E. J. Brouwer

Classical logic Computability logic Deontic logic Dependence logic Description logic Deviant logic Doxastic logic Epistemic logic First-order logic Formal