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 theory -- Argumentum ad baculum -- Argumentum e contrario -- Ariadne's thread (logic) -- Aristotelian logic -- Aristotle -- Association for Informal Logic and Critical Thinking -- Association for Logic, Language and Information -- Association for Symbolic Logic -- Attacking Faulty Reasoning -- Australasian Association for Logic -- Axiom -- Axiom independence -- Axiom of reducibility -- Axiomatic system -- Axiomatization --
Backward chaining -- Barcan formula -- Begging the question -- Begriffsschrift -- Belief -- Belief bias -- Belief revision -- Benson Mates -- Bertrand Russell Society -- Biconditional elimination -- Biconditional introduction -- Bivalence and related laws -- Blue and Brown Books -- Boole's syllogistic -- Boolean algebra (logic) -- Boolean algebra (structure) -- Boolean network --
Canonical form -- Canonical form (Boolean algebra) -- Cartesian circle -- Case-based reasoning -- Categorical logic -- Categories (Aristotle) -- Categories (Peirce) -- Category mistake -- Catuṣkoṭi -- Circular definition -- Circular reasoning -- Circular reference -- Circular reporting -- Circumscription (logic) -- Circumscription (taxonomy) -- Classical logic -- Clocked logic -- Cognitive bias -- Cointerpretability -- Colorless green ideas sleep furiously -- Combinational logic -- Combinatory logic -- Combs method -- Common knowledge (logic) -- Commutativity of conjunction -- Completeness (logic) -- Composition of Causes -- Compossibility -- Comprehension (logic) -- Computability logic -- Concept -- Conceptualism -- Condensed detachment -- Conditional disjunction -- Conditional probability -- Conditional proof -- Conditional quantifier -- Confirmation bias -- Conflation -- Confusion of the inverse -- Conjunction elimination -- Conjunction fallacy -- Conjunction introduction -- Conjunctive normal form -- Connexive logic -- Connotation -- Consequent -- Consistency -- Constructive dilemma -- Contra principia negantem non est disputandum -- Contradiction -- Contrapositive -- Control logic -- Conventionalism -- Converse (logic) -- Converse Barcan formula -- Correlative-based fallacies -- Counterexample -- Counterfactual conditional -- Counterintuitive -- Cratylism -- Credibility -- Criteria of truth -- Critical-Creative Thinking and Behavioral Research Laboratory -- Critical pedagogy -- Critical reading -- Critical thinking -- Critique of Pure Reason -- Curry's paradox -- Cyclic negation --
Dagfinn Føllesdal -- De Interpretatione -- De Morgan's laws -- Decidability (logic) -- Decidophobia -- Decision making -- Decisional balance sheet -- Deductive closure -- Deduction theorem -- Deductive fallacy -- Deductive reasoning -- Default logic -- Defeasible logic -- Defeasible reasoning -- Definable set -- Definist fallacy -- Definition -- Definitions of logic -- Degree of truth -- Denying the antecedent -- Denying the correlative -- Deontic logic -- Description -- Description logic -- Descriptive fallacy -- Deviant logic -- Dharmakirti -- Diagrammatic reasoning -- Dialectica -- Dialectica space -- Dialetheism -- Dichotomy -- Difference (philosophy) -- Digital timing diagram -- Dignāga -- Dilemma -- Disjunction elimination -- Disjunction introduction -- Disjunctive normal form -- Disjunctive syllogism -- Dispositional and occurrent belief -- Disquotational principle -- Dissoi logoi -- Division of Logic, Methodology, and Philosophy of Science -- Don't-care term -- Donald Davidson (philosopher) -- Double counting (fallacy) -- Double negation -- Double negative -- Double negation elimination -- Doxa -- Drinking the Kool-Aid --
EL++ -- Ecological fallacy -- Effective method -- Elimination rule -- Emotional reasoning -- Emotions in decision-making -- Empty name -- Encyclopedia of the Philosophical Sciences -- End term -- Engineered language -- Entailment -- Entitative graph -- Enumerative definition -- Epicureanism -- Epilogism -- Epistemic closure -- Equisatisfiability -- Erotetics -- Eternal statement -- Etymological fallacy -- European Summer School in Logic, Language and Information -- Evidence -- Exclusive nor -- Exclusive or -- Existential fallacy -- Existential graph -- Existential quantification -- Expert -- Explanandum -- Explanation -- Explanatory power -- Extension (semantics) -- Extensional context -- Extensional definition --
Fa (concept) -- Fact -- Fallacies of definition -- Fallacy -- Fallacy of distribution -- Fallacy of four terms -- Fallacy of quoting out of context -- Fallacy of the four terms -- False attribution -- False dilemma -- False equivalence -- False premise -- Fictionalism -- Finitary relation -- Finite model property -- First-order logic -- First-order predicate -- First-order predicate calculus -- First-order resolution -- Fitch-style calculus -- Fluidic logic -- Fluidics -- Formal fallacy -- Formal ontology -- Formal system -- Formalism (philosophy) -- Forward chaining -- Free logic -- Free variables and bound variables -- Function and Concept -- Fuzzy logic --
Game semantics -- Ganto's Ax -- Geometry of interaction -- Gilles-Gaston Granger -- Gongsun Long -- Grammaticality -- Greedy reductionism -- Grundlagen der Mathematik --
HPO formalism -- Halo effect -- Handbook of Automated Reasoning -- Hanlon's razor -- Hasty generalization -- Herbrandization -- Hetucakra -- Heyting algebra -- Higher-order predicate -- Higher-order thinking -- Historian's fallacy -- Historical fallacy -- History of logic -- History of the function concept -- Hold come what may -- Homunculus argument -- Horn clause -- Hume's fork -- Hume's principle -- Hypothetical syllogism --
Identity (philosophy) -- Identity of indiscernibles -- Idola fori -- Idola specus -- Idola theatri -- Idola tribus -- If-by-whiskey -- Iff -- Illicit major -- Illicit minor -- Illuminationism -- Immutable truth -- Imperative logic -- Implicant -- Inclusion (logic) -- Incomplete comparison -- Inconsistent comparison -- Inconsistent triad -- Independence-friendly logic -- Indian logic -- Inductive logic -- Inductive logic programming -- Inference -- Inference procedure -- Inference rule -- Inferential role semantics -- Infinitary logic -- Infinite regress -- Infinity -- Informal fallacy -- Informal logic -- Inquiry -- Inquiry (philosophy journal) -- Insolubilia -- Institute for Logic, Language and Computation -- Intellectual responsibility -- Intended interpretation -- Intension -- Intensional fallacy -- Intensional logic -- Intensional statement -- Intentional Logic -- Intermediate logic -- Interpretability -- Interpretability logic -- Interpretive discussion -- Introduction rule -- Introduction to Mathematical Philosophy -- Intuitionistic linear logic -- Intuitionistic logic -- Invalid proof -- Inventor's paradox -- Inverse (logic) -- Inverse consequences -- Irreducibility -- Is Logic Empirical? -- Isagoge -- Ivor Grattan-Guinness --
Jacobus Naveros -- Jayanta Bhatta -- Jingle-jangle fallacies -- John Corcoran (logician) -- John W. Dawson, Jr -- Journal of Applied Non-Classical Logics -- Journal of Automated Reasoning -- Journal of Logic, Language and Information -- Journal of Logic and Computation -- Journal of Mathematical Logic -- Journal of Philosophical Logic -- Journal of Symbolic Logic -- Judgment (mathematical logic) -- Judgmental language -- Just-so story --
Karnaugh map -- Kinetic logic -- Knowing and the Known -- Kripke semantics -- Kurt Gödel Society --
Language -- Language, Proof and Logic -- Lateral thinking -- Law of excluded middle -- Law of identity -- Law of non-contradiction -- Law of noncontradiction -- Law of thought -- Laws of Form -- Laws of logic -- Leap of faith -- Lemma (logic) -- Lexical definition -- Linear logic -- Linguistic and Philosophical Investigations -- Linguistics and Philosophy -- List of fallacies -- List of incomplete proofs -- List of logic journals -- List of paradoxes -- Logic -- Logic Lane -- Logic Spectacles -- Logic gate -- Logic in China -- Logic in Islamic philosophy -- Logic of class -- Logic of information -- Logic programming -- Logica Universalis -- Logica nova -- Logical Analysis and History of Philosophy -- Logical Investigations (Husserl) -- Logical Methods in Computer Science -- Logical abacus -- Logical argument -- Logical assertion -- Logical atomism -- Logical biconditional -- Logical conditional -- Logical conjunction -- Logical constant -- Logical disjunction -- Logical equality -- Logical equivalence -- Logical extreme -- Logical form -- Logical harmony -- Logical holism -- Logical NAND -- Logical NOR -- Logical operator -- Logical quality -- Logical truth -- Logicism -- Logico-linguistic modeling -- Logos -- Loosely associated statements -- Łoś–Tarski preservation theorem -- Ludic fallacy -- Lwów–Warsaw school of logic --
Main contention -- Major term -- Markov's principle -- Martin Gardner bibliography -- Masked-man fallacy -- Material conditional -- Mathematical fallacy -- Mathematical logic -- Meaning (linguistics) -- Meaning (non-linguistic) -- Meaning (philosophy of language) -- Meaningless statement -- Megarian school -- Mental model theory of reasoning -- Mereology -- Meta-communication -- Metalanguage -- Metalogic -- Metamathematics -- Metasyntactic variable -- Metatheorem -- Metavariable -- Middle term -- Minimal axioms for Boolean algebra -- Minimal logic -- Minor premise -- Miscellanea Logica -- Missing dollar riddle -- Modal fallacy -- Modal fictionalism -- Modal logic -- Model theory -- Modus ponens -- Modus tollens -- Moral reasoning -- Motivated reasoning -- Moving the goalposts -- Multigrade predicate -- Multi-valued logic -- Multiple-conclusion logic -- Mutatis mutandis -- Mutual knowledge (logic) -- Mutually exclusive events -- Münchhausen trilemma --
Naive set theory -- Name -- Narrative logic -- Natural deduction -- Natural kind -- Natural language -- Necessary and sufficient -- Necessity and sufficiency -- Negation -- Neutrality (philosophy) -- Nirvana fallacy -- Nixon diamond -- No true Scotsman -- Nominal identity -- Non-Aristotelian logic -- Non-classical logic -- Non-monotonic logic -- Non-rigid designator -- Non sequitur (logic) -- Noneism -- Nonfirstorderizability -- Nordic Journal of Philosophical Logic -- Normal form (natural deduction) -- Novum Organum -- Nyaya -- Nyāya Sūtras --
Object of the mind -- Occam's razor -- On Formally Undecidable Propositions of Principia Mathematica and Related Systems -- One-sided argument -- Ontological commitment -- Open sentence -- Opinion -- Opposing Viewpoints series -- Ordered logic -- Organon -- Original proof of Gödel's completeness theorem -- Osmund Lewry -- Ostensive definition -- Outline of logic -- Overbelief --
Package-deal fallacy -- Panlogism -- Paraconsistent logic -- Paraconsistent logics -- Parade of horribles -- Paradox -- Pars destruens/pars construens -- Pathetic fallacy -- Persuasive definition -- Peter Simons (academic) -- Philosophia Mathematica -- Philosophical logic -- Philosophy of logic -- Peirce's law -- Plural quantification -- Poisoning the well -- Polarity item -- Polish Logic -- Polish notation -- Politician's syllogism -- Polychotomous key -- Polylogism -- Polysyllogism -- Port-Royal Logic -- Possible world -- Post's lattice -- Post disputation argument -- Post hoc ergo propter hoc -- Posterior Analytics -- Practical syllogism -- Pragmatic mapping -- Pragmatic maxim -- Pragmatic theory of truth -- Pramāṇa -- Pramāṇa-samuccaya -- Precising definition -- Precision questioning -- Predicable -- Predicate (logic) -- Predicate abstraction -- Predicate logic -- Preferential entailment -- Preintuitionism -- Prescriptivity -- Presentism (historical analysis) -- Presupposition -- Principia Mathematica -- Principle of bivalence -- Principle of explosion -- Principle of nonvacuous contrast -- Principle of sufficient reason -- Principles of Mathematical Logic -- Prior Analytics -- Private Eye Project -- Pro hominem -- Probabilistic logic -- Probabilistic logic network -- Problem of future contingents -- Problem of induction -- Process of elimination -- Project Reason -- Proof-theoretic semantics -- Proof (truth) -- Proof by assertion -- Proof theory -- Propaganda techniques -- Proposition -- Propositional calculus -- Propositional function -- Propositional representation -- Propositional variable -- Prosecutor's fallacy -- Provability logic -- Proving too much -- Prudence -- Pseudophilosophy -- Psychologism -- Psychologist's fallacy --
Q.E.D. -- Quantification -- Quantization (linguistics) -- Quantum logic --
Ramism -- Rationality -- Razor (philosophy) -- Reason -- Reductio ad absurdum -- Reference -- Reflective equilibrium -- Regression fallacy -- Regular modal logic -- Reification (fallacy) -- Relativist fallacy -- Relevance -- Relevance logic -- Relevant logic -- Remarks on the Foundations of Mathematics -- Retroduction -- Retrospective determinism -- Revolutions in Mathematics -- Rhetoric -- Rigour -- Rolandas Pavilionis -- Round square copula -- Rudolf Carnap -- Rule of inference -- Rvachev function --
SEE-I -- Salva congruitate -- Salva veritate -- Satisfiability -- Scholastic logic -- School of Names -- Science of Logic -- Scientific temper -- Second-order predicate -- Segment addition postulate -- Self-reference -- Self-refuting idea -- Self-verifying theories -- Semantic theory of truth -- Semantics -- Sense and reference -- Sequent -- Sequent calculus -- Sequential logic -- Set (mathematics) -- Seven Types of Ambiguity (Empson) -- Sheffer stroke -- Ship of Theseus -- Simple non-inferential passage -- Singular term -- Situation -- Situational logic -- Skeptic's Toolbox -- Slingshot argument -- Social software (social procedure) -- Socratic questioning -- Soku hi -- Some Remarks on Logical Form -- Sophism -- Sophistical Refutations -- Soundness -- Source credibility -- Source criticism -- Special case -- Specialization (logic) -- Speculative reason -- Spurious relationship -- Square of opposition -- State of affairs (philosophy) -- Statement (logic) -- Straight and Crooked Thinking -- Straight face test -- Straw man -- Strength (mathematical logic) -- Strict conditional -- Strict implication -- Strict logic -- Structural rule -- Studia Logica -- Studies in Logic, Grammar and Rhetoric -- Subjective logic -- Substitution (logic) -- Substructural logic -- Sufficient condition -- Sum of Logic -- Sunk costs -- Supertask -- Supervaluationism -- Supposition theory -- Survivorship bias -- Syllogism -- Syllogistic fallacy -- Symbol (formal) -- Syntactic Structures -- Syntax (logic) -- Synthese -- Systems of Logic Based on Ordinals --
T-schema -- Tacit assumption -- Tarski's undefinability theorem -- Tautology (logic) -- Temporal logic -- Temporal parts -- Teorema (journal) -- Term (argumentation) -- Term logic -- Ternary logic -- Testability -- Tetralemma -- Textual case based reasoning -- The False Subtlety of the Four Syllogistic Figures -- The Foundations of Arithmetic -- The Geography of Thought -- The Laws of Thought -- The Paradoxes of the Infinite -- Theorem -- Theoretical definition -- Theory and Decision -- Theory of justification -- Theory of obligationes -- Third-cause fallacy -- Three men make a tiger -- Tolerance (in logic) -- Topical logic -- Topics (Aristotle) -- Tractatus Logico-Philosophicus -- Train of thought -- Trairūpya -- Transferable belief model -- Transparent Intensional Logic -- TregoED -- Trikonic -- Trilemma -- Trivial objections -- Trivialism -- Truth -- Truth-bearer -- Truth condition -- Truth function -- Truth value -- Truthiness -- Truthmaker -- Type (model theory) -- Type theory -- Type–token distinction --
Ultrafinitism -- Unification (computer science) -- Unifying theories in mathematics -- Uniqueness quantification -- Universal logic -- Universal quantification -- Univocity -- Unspoken rule -- Use–mention distinction --
Vacuous truth -- Vagrant predicate -- Vagueness -- Validity -- Valuation-based system -- Van Gogh fallacy -- Venn diagram -- Vicious circle principle --
Warnier/Orr diagram -- Well-formed formula -- What the Tortoise Said to Achilles -- Willard Van Orman Quine -- William Kneale -- Window operator -- Wisdom of repugnance -- Witness (mathematics) -- Word sense --
Zhegalkin polynomial --
