Logic

Argumentation theory, or argumentation, is the interdisciplinary study of how conclusions can be reached through logical reasoning; that is, claims based, soundly or not, on premises.

In logic, and especially in its applications to mathematics and philosophy, a counterexample is an exception to a proposed general rule or law.

Turned A (capital: Ɐ, lowercase: ɐ, math symbol ∀) is a symbol based upon the letter A.

In argumentation theory, an argumentum ad populum (Latin for "appeal to the people") is a fallacious argument that concludes that a proposition is true because many or most people believe it: "If many believe so, it is so.

Case-based reasoning (CBR), broadly construed, is the process of solving new problems based on the solutions of similar past problems.

A heuristic technique (/hjᵿˈrɪstᵻk/; Ancient Greek: εὑρίσκω, "find" or "discover"), often called simply a heuristic, is any approach to problem solving, learning, or discovery that employs a practical method not guaranteed to be optimal or perfect, but sufficient for the immediate goals.

Inferences are steps in reasoning, moving from premises to conclusions.

Informal logic, intuitively, refers to the principles of logic and logical thought outside of a formal setting.

Kripke semantics (also known as relational semantics or frame semantics, and often confused with possible world semantics) is a formal semantics for non-classical logic systems created in the late 1950s and early 1960s by Saul Kripke and André Joyal.

Occam's razor (also written as Ockham's razor, and lex parsimoniae in Latin, which means law of parsimony) is a problem-solving principle attributed to William of Ockham (c. 1287–1347), who was an English Franciscan friar, scholastic philosopher and theologian.

For example, in arithmetic, it allows the expression of the statement that every natural number has a successor.

A truth table is a mathematical table used in logic—specifically in connection with Boolean algebra, boolean functions, and propositional calculus—which sets out the functional values of logical expressions on each of their functional arguments, that is, for each combination of values taken by their logical variables (Enderton, 2001).

Critical thinking, also called critical analysis, is clear, rational thinking involving critique.

A question is a linguistic expression used to make a request for information, or the request made using such an expression.

A polemic /pəˈlɛmɪk/ is a contentious argument that is intended to support a specific position via attacks on a contrary position.

This is a list of paradoxes, grouped thematically.

In the branch of linguistics known as pragmatics, a presupposition (or ps) is an implicit assumption about the world or background belief relating to an utterance whose truth is taken for granted in discourse.

Analogy (from Greek ἀναλογία, analogia, "proportion") is a cognitive process of transferring information or meaning from a particular subject (the analogue or source) to another (the target), or a linguistic expression corresponding to such a process.

Argument from ignorance (from Latin: argumentum ad ignorantiam), also known as appeal to ignorance (in which ignorance represents "a lack of contrary evidence"), is a fallacy in informal logic.

A generalization (or generalisation) is a concept in the inductive sense of that word, or an extension of a concept to less-specific English or mathematical criteria.

Metamathematics is the study of mathematics itself using mathematical methods.

Nonsense is a communication, via speech, writing, or any other symbolic system, that lacks any coherent meaning.

The principle of sufficient reason states that everything must have a reason or a cause.

Self-reference occurs in natural or formal languages when a sentence, idea or formula refers to itself.

A polysyllogism (also called multi-premise syllogism, sorites, climax, or gradatio) is a string of any number of propositions forming together a sequence of syllogisms such that the conclusion of each syllogism, together with the next proposition, is a premise for the next, and so on.

A dichotomy /daɪˈkɒtəmi/ is a partition of a whole (or a set) into two parts (subsets).

In epistemology, the burden of proof (Latin: onus probandi (shorthand for Onus probandi incumbit ei qui dicit, non ei qui negat)) is the obligation on a party in a dispute to provide sufficient warrant for their position.

Apophasis (Greek ἀπόφασις from ἀπόφημι apophemi, "to say no") is a rhetorical device wherein the speaker or writer brings up a subject by either denying it, or denying that it should be brought up.

A System of Logic --A priori and a posteriori --Abacus logic --Abduction (logic) --Abductive validation --Academia Analitica --Accuracy and precision --Ad captandum --Ad hoc hypothesis --Ad hominem --Affine logic --Affirming the antecedent --Affirming the consequent --Algebraic logic --Ambiguity --Analysis --Analysis (journal) --Analytic reasoning --Analytic–synthetic distinction --Anangeon --Anecdotal evidence --Antecedent (logic) --Antepredicament --Anti-psychologism --Antinomy --Apophasis --Appeal to probability --Appeal to ridicule --Archive for Mathematical Logic --Arché --Argument --Argument by example --Argument form --Argument from authority --Argument map --Argumentation ethics --Argumentation theory --Argumentum ad baculum --Argumentum e contrario --Ariadne's thread (logic) --Ari