Outline of logic
Logic is the formal science of using reason and is considered a branch of both philosophy and mathematics and to a lesser extent computer science. Logic investigates and classifies the structure of statements and arguments, both through the study of formal systems of inference and the study of arguments in natural language. The scope of logic can therefore be very large, ranging from core topics such as the study of fallacies and paradoxes, to specialized analyses of reasoning such as probability, correct reasoning, and arguments involving causality. One of the aims of logic is to identify the correct and incorrect inferences. Logicians study the criteria for the evaluation of arguments.
Foundations of logic
- Analytic-synthetic distinction
- Antinomy
- A priori and a posteriori
- Definition
- Description
- Entailment
- Identity
- Inference
- Logical form
- Logical implication
- Logical truth
- Logical consequence
- Name
- Necessity
- Material conditional
- Meaning
- Meaning
- Paradox
- Possible world
- Presupposition
- Probability
- Quantification
- Reason
- Reasoning
- Reference
- Semantics
- Strict conditional
- Syntax
- Truth
- Truth value
- Validity
Philosophical logic
Informal logic and critical thinking
- Argument
- Argument map
- Accuracy and precision
- Ad hoc hypothesis
- Ambiguity
- Analysis
- Attacking Faulty Reasoning
- Belief
- Belief bias
- Bias
- Cognitive bias
- Confirmation bias
- Credibility
- Critical pedagogy
- Critical reading
- Decidophobia
- Decision making
- Dispositional and occurrent belief
- Emotional reasoning
- Evidence
- Expert
- Explanation
- Explanatory power
- Fact
- Fallacy
- Higher-order thinking
- Inquiry
- Interpretive discussion
- Narrative logic
- Occam's razor
- Opinion
- Practical syllogism
- Precision questioning
- Propaganda
- Propaganda techniques
- Prudence
- Pseudophilosophy
- Reasoning
- Relevance
- Rhetoric
- Rigour
- Socratic questioning
- Source credibility
- Source criticism
- Theory of justification
- Topical logic
- Vagueness
Deductive reasoning
Theories of deduction
- Anti-psychologism
- Conceptualism
- Constructivism
- Conventionalism
- Counterpart theory
- Deflationary theory of truth
- Dialetheism
- Fictionalism
- Formalism
- Game theory
- Illuminationist philosophy
- Logical atomism
- Logical holism
- Logicism
- Modal fictionalism
- Nominalism
- Object theory
- Polylogism
- Pragmatism
- Preintuitionism
- Proof theory
- Psychologism
- Ramism
- Semantic theory of truth
- Sophism
- Trivialism
- Ultrafinitism
Fallacies
- Fallacy - incorrect argumentation in reasoning resulting in a misconception or presumption. By accident or design, fallacies may exploit emotional triggers in the listener or interlocutor, or take advantage of social relationships between people. Fallacious arguments are often structured using rhetorical patterns that obscure any logical argument. Fallacies can be used to win arguments regardless of the merits. There are dozens of types of fallacies.
Formal logic
- Formal logic - Mathematical logic, symbolic logic and formal logic are largely, if not completely synonymous. The essential feature of this field is the use of formal languages to express the ideas whose logical validity is being studied.
- * List of mathematical logic topics
Symbols and strings of symbols
Logical symbols
- Logical variables
- *Propositional variable
- *Predicate variable
- *Literal
- *Metavariable
- Logical constants
- *Logical connective
- *Quantifier
- *Identity
- *Brackets
Logical connectives
- Converse implication
- Converse nonimplication
- Exclusive or
- Logical NOR
- Logical biconditional
- Logical conjunction
- Logical disjunction
- Material implication
- Material nonimplication
- Negation
- Sheffer stroke
Strings of symbols
- Atomic formula
- Open sentence
Types of propositions
- Analytic proposition
- Axiom
- Atomic sentence
- Clause
- Contingent proposition
- Contradiction
- Logical truth
- Propositional formula
- Rule of inference
- Sentence
- Sequent
- Statement
- Tautology
- Theorem
Rules of inference
- Biconditional elimination
- Biconditional introduction
- Case analysis
- Commutativity of conjunction
- Conjunction introduction
- Constructive dilemma
- Contraposition
- Conversion
- De Morgan's laws
- Destructive dilemma
- Disjunction elimination
- Disjunction introduction
- Disjunctive syllogism
- Double negation elimination
- Generalization
- Hypothetical syllogism
- Law of excluded middle
- Law of identity
- Modus ponendo tollens
- Modus ponens
- Modus tollens
- Obversion
- Principle of contradiction
- Resolution
- Simplification
- Transposition
Formal theories
- Formal proof
- List of first-order theories
Expressions in an object language
- Symbol
- Formula
- Formal system
- Theorem
- Formal proof
- Theory
Expressions in a metalanguage
- Metalinguistic variable
- Deductive system
- Metatheorem
- Metatheory
- Interpretation
Propositional and boolean logic
Propositional logic
- Absorption law
- Clause
- Deductive closure
- Entailment
- Formation rule
- Functional completeness
- Intermediate logic
- Literal
- Logical connective
- Logical consequence
- Negation normal form
- Open sentence
- Propositional calculus
- Propositional formula
- Propositional variable
- Rule of inference
- Strict conditional
- Substitution instance
- Truth table
- Zeroth-order logic
Boolean logic
- Boolean algebra
- Boolean logic
- Boolean algebra
- Boolean algebras canonically defined
- Introduction to Boolean algebra
- Complete Boolean algebra
- Free Boolean algebra
- Monadic Boolean algebra
- Residuated Boolean algebra
- Two-element Boolean algebra
- Modal algebra
- Derivative algebra
- Relation algebra
- Absorption law
- Laws of Form
- De Morgan's laws
- Algebraic normal form
- Canonical form
- Boolean conjunctive query
- Boolean-valued model
- Boolean domain
- Boolean expression
- Boolean ring
- Boolean function
- Boolean-valued function
- Parity function
- Symmetric Boolean function
- Conditioned disjunction
- Field of sets
- Functional completeness
- Implicant
- Logic alphabet
- Logic redundancy
- Logical connective
- Logical matrix
- Product term
- True quantified Boolean formula
- Truth table
Predicate logic and relations
Predicate logic
- Atomic formula
- Atomic sentence
- Domain of discourse
- Empty domain
- Extension
- First-order logic
- First-order predicate
- Formation rule
- Free variables and bound variables
- Generalization
- Monadic predicate calculus
- Predicate
- Predicate logic
- Predicate variable
- Quantification
- Second-order predicate
- Sentence
- Universal instantiation
Relations
- Finitary relation
- Antisymmetric relation
- Asymmetric relation
- Bijection
- Bijection, injection and surjection
- Binary relation
- Composition of relations
- Congruence relation
- Converse relation
- Coreflexive relation
- Covering relation
- Cyclic order
- Dense relation
- Dependence relation
- Dependency relation
- Directed set
- Equivalence relation
- Euclidean relation
- Homogeneous relation
- Idempotence
- Intransitivity
- Involutive relation
- Partial equivalence relation
- Partial function
- Partially ordered set
- Preorder
- Prewellordering
- Propositional function
- Quasitransitive relation
- Reflexive relation
- Surjective function
- Symmetric relation
- Ternary relation
- Total relation
- Transitive relation
- Trichotomy
- Well-founded relation
Mathematical logic
Set theory
- Aleph null
- Bijection, injection and surjection
- Binary set
- Cantor's diagonal argument
- Cantor's first uncountability proof
- Cantor's theorem
- Cardinality of the continuum
- Cardinal number
- Codomain
- Complement
- Constructible universe
- Continuum hypothesis
- Countable set
- Decidable set
- Denumerable set
- Disjoint sets
- Disjoint union
- Domain of a function
- Effective enumeration
- Element
- Empty function
- Empty set
- Enumeration
- Extensionality
- Finite set
- Forcing
- Function
- Function composition
- Generalized continuum hypothesis
- Index set
- Infinite set
- Intension
- Intersection
- Inverse function
- Large cardinal
- Löwenheim–Skolem theorem
- Map
- Multiset
- Morse–Kelley set theory
- Naïve set theory
- One-to-one correspondence
- Ordered pair
- Partition of a set
- Pointed set
- Power set
- Projection
- Proper subset
- Proper superset
- Range of a function
- Russell's paradox
- Sequence
- Set
- Set of all sets
- Simple theorems in the algebra of sets
- Singleton
- Skolem paradox
- Subset
- Superset
- Tuple
- Uncountable set
- Union
- Von Neumann–Bernays–Gödel set theory
- Zermelo set theory
- Zermelo–Fraenkel set theory
Metalogic
- Completeness
- Syntax
- Consistency
- Decidability
- Deductive system
- Interpretation
- Cantor's theorem
- Church's theorem
- Church's thesis
- Effective method
- Formal system
- Gödel's completeness theorem
- Gödel's first incompleteness theorem
- Gödel's second incompleteness theorem
- Independence
- Logical consequence
- Löwenheim–Skolem theorem
- Metalanguage
- Metasyntactic variable
- Metatheorem
- Object language
- Symbol
- Type–token distinction
- Use–mention distinction
- Well-formed formula
Proof theory
- Axiom
- Deductive system
- Formal proof
- Formal system
- Formal theorem
- Syntactic consequence
- Syntax
- Transformation rules
Model theory
- Interpretation
- Logical validity
- Non-standard model
- Normal model
- Model
- Semantic consequence
- Truth value
Computability theory
- Alpha recursion theory
- Arithmetical set
- Church–Turing thesis
- Computability logic
- Computable function
- Computation
- Decision problem
- Effective method
- Entscheidungsproblem
- Enumeration
- Forcing
- Halting problem
- History of the Church–Turing thesis
- Lambda calculus
- List of undecidable problems
- Post correspondence problem
- Post's theorem
- Primitive recursive function
- Recursion
- Recursive language
- Recursive set
- Recursively enumerable language
- Recursively enumerable set
- Reduction
- Turing machine
Classical logic
- Properties of classical logics:
- * Law of the excluded middle
- * Double negation elimination
- * Law of noncontradiction
- * Principle of explosion
- * Monotonicity of entailment
- * Idempotency of entailment
- * Commutativity of conjunction
- * De Morgan duality - every logical operator is dual to another
- Term logic
- General concepts in classical logic
- * Baralipton
- * Baroco
- * Bivalence
- * Boolean logic
- * Boolean-valued function
- * Categorical proposition
- * Distribution of terms
- * End term
- * Enthymeme
- * Immediate inference
- * Law of contraries
- * Logical connective
- * Major term
- * Middle term
- * Minor term
- * Organon
- * Polysyllogism
- * Port-Royal Logic
- * Premise
- * Prior Analytics
- * Relative term
- * Sorites paradox
- * Square of opposition
- * Sum of Logic
- * Syllogism
- * Tetralemma
- * Truth function
Non-classical logic
- Affine logic
- Bunched logic
- Computability logic
- Decision theory
- Description logic
- Deviant logic
- Free logic
- Fuzzy logic
- Game theory
- Intensional logic
- Intuitionistic logic
- Linear logic
- Many-valued logic
- Minimal logic
- Non-monotonic logic
- Noncommutative logic
- Paraconsistent logic
- Probability theory
- Quantum logic
- Relevance logic
- Strict logic
- Substructural logic
Modal logic
- Alethic logic
- Deontic logic
- Doxastic logic
- Epistemic logic
- Temporal logic
Concepts of logic
- Deductive reasoning
- Inductive reasoning
- Abductive reasoning
- Proof theory
- Set theory
- Formal system
- * Predicate logic
- ** Predicate
- ** Higher-order logic
- * Propositional calculus
- ** Proposition
- Boolean algebra
- * Boolean logic
- * Truth value
- * Venn diagram
- * Peirce's law
- Aristotelian logic
- Non-Aristotelian logic
- Informal logic
- Fuzzy logic
- Infinitary logic
- * Infinity
- Categorical logic
- Linear logic
- Metalogic
- order
- Ordered logic
- Temporal logic
- Sequential logic
- Provability logic
- * Interpretability logic
- ** Interpretability
- Quantum logic
- Relevant logic
- Consequent
- Affirming the consequent
- Antecedent
- Denying the antecedent
- Theorem
- Axiom
- Axiomatic system
- Axiomatization
- Conditional proof
- Invalid proof
- Degree of truth
- Truth
- Truth condition
- Truth function
- Double negation
- * Double negation elimination
- Fallacy
- * Existential fallacy
- * Logical fallacy
- * Syllogistic fallacy
- Type theory
- Game theory
- Game semantics
- Rule of inference
- Inference procedure
- Inference rule
- Introduction rule
- Law of excluded middle
- Law of non-contradiction
- Logical constant
- * Logical connective
- * Quantifier
- Logic gate
- * Boolean Function
- Tautology
- Logical assertion
- Logical conditional
- Logical biconditional
- Logical equivalence
- Logical AND
- Negation
- Logical OR
- Logical NAND
- Logical NOR
- Contradiction
- Logicism
- Polysyllogism
- Syllogism
- Hypothetical syllogism
- Major premise
- Minor premise
- Term
- Singular term
- Major term
- Middle term
- Quantification
- Plural quantification
- Logical argument
- * Validity
- * Soundness
- Inverse
- Non sequitur
- Tolerance
- Satisfiability
- Logical language
- Paradox
- Polish notation
- Principia Mathematica
- Quod erat demonstrandum
- Reductio ad absurdum
- Rhetoric
- Self-reference
- Necessary and sufficient
- Sufficient condition
- Nonfirstorderizability
- Occam's Razor
- Socratic dialogue
- Socratic method
- Argument form
- Logic programming
- Unification
History of logic
Literature about logic
Journals
- Journal of Logic, Language and Information
- Journal of Philosophical Logic
- Linguistics and Philosophy
Books
- A System of Logic
- Attacking Faulty Reasoning
- Begriffsschrift
- Categories
- Charles Sanders Peirce bibliography
- De Interpretatione
- Gödel, Escher, Bach
- Introduction to Mathematical Philosophy
- Language, Truth, and Logic
- Laws of Form
- Novum Organum
- On Formally Undecidable Propositions of Principia Mathematica and Related Systems
- Organon
- Philosophy of Arithmetic
- Polish Logic
- Port-Royal Logic
- Posterior Analytics
- Principia Mathematica
- Principles of Mathematical Logic
- Prior Analytics
- Rhetoric
- Sophistical Refutations
- Sum of Logic
- The Art of Being Right
- The Foundations of Arithmetic
- Topics
- Tractatus Logico-Philosophicus
Logic organizations
- Association for Symbolic Logic
Logicians
- List of logicians
- List of philosophers of language