Non-classical logics (and sometimes alternative logics or non-Aristotelian logics) are formal systems that differ in a significant way from standard logical...

Classical logic (or standard logic) or Frege–Russell logic is the intensively studied and most widely used class of deductive logic. Classical logic has...

A non-monotonic logic is a formal logic whose entailment relation is not monotonic. In other words, non-monotonic logics are devised to capture and represent...

An Introduction to Non-Classical Logic is a 2001 mathematics textbook by philosopher and logician Graham Priest, published by Cambridge University Press...

An important issue for philosophical logic is the question of how to classify the great variety of non-classical logical systems, many of which are of...

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

Paraconsistent logic is a type of non-classical logic that allows for the coexistence of contradictory statements without leading to a logical explosion...

Linear logic is a substructural logic proposed by French logician Jean-Yves Girard as a refinement of classical and intuitionistic logic, joining the...

study of non-classical logic (such as intuitionistic logic), and in the study of modal logic. Interpretations used to study non-classical logic include...

and lack certainty. Fuzzy logic has been applied to many fields, from control theory to artificial intelligence. Classical logic only permits conclusions...

Independence-friendly logic (IF logic; proposed by Jaakko Hintikka and Gabriel Sandu [fr] in 1989) is an extension of classical first-order logic (FOL) by means...

In logic, a substructural logic is a logic lacking one of the usual structural rules (e.g. of classical and intuitionistic logic), such as weakening,...

opposed to classical logic, which is a formal theory of truth. It was introduced and so named by Giorgi Japaridze in 2003. In classical logic, formulas...

logic, sometimes more generally called constructive logic, refers to systems of symbolic logic that differ from the systems used for classical logic by...

Default logic is a non-monotonic logic proposed by Raymond Reiter to formalize reasoning with default assumptions. Default logic can express facts like...

abstractly). No “non-constructive” proofs are allowed (like the classic proof by contradiction without a witness). The main constructive logics are the following:...

agree that quantum logic is not a competitor to classical logic. It is far from evident (albeit true) that quantum logic is a logic, in the sense of describing...

for non-classical logic systems created in the late 1950s and early 1960s by Saul Kripke and André Joyal. It was first conceived for modal logics, and...

Deviant logic is a type of logic incompatible with classical logic. Philosopher Susan Haack uses the term deviant logic to describe certain non-classical systems...

In mathematical logic, a superintuitionistic logic is a propositional logic extending intuitionistic logic. Classical logic is the strongest consistent...

formal logic, an important distinction is between classical and non-classical logic. The term classical logic refers primarily to propositional logic and...

A free logic is a logic with fewer existential presuppositions than classical logic. Free logics may allow for terms that do not denote any object. Free...

modal logic. It is logically equivalent to the material conditional of classical logic, combined with the necessity operator from modal logic. For any...

paradoxes), and his many writings related to paraconsistent and other non-classical logics. In these he draws on the history of philosophy, including Asian...

contrasted with the more commonly known bivalent logics (such as classical sentential or Boolean logic) which provide only for true and false. Emil Leon...

rely upon formulas such as p ∧ ¬p and ¬(p → p). In both Boolean logic and Classical logic systems, true and false are opposite with respect to negation;...

Probabilistic logic (also probability logic and probabilistic reasoning) involves the use of probability and logic to deal with uncertain situations. Probabilistic...

In logic, philosophy, and theoretical computer science, dynamic logic is an extension of modal logic capable of encoding properties of computer programs...

Paradox – Logically self-contradictory statement Relevance logic – A kind of non-classical logic Scientific misconceptions – False beliefs about science...

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