Outline of logic

Outline of logic

The following outline is provided as an overview of and topical guide to logic:

Logicformal science of using reason and is considered a branch of both philosophy and mathematics. Logic investigates and classifies the structure of statements and arguments, both through the study of formal systems of inference and through 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 (or valid) and incorrect (or fallacious) inferences. Logicians study the criteria for the evaluation of arguments.


  • Foundations of logic 1
  • Philosophical logic 2
    • Informal logic and critical thinking 2.1
    • Deductive reasoning 2.2
      • Theories of deduction 2.2.1
    • Fallacies 2.3
  • Formal logic 3
    • Symbols and strings of symbols 3.1
      • Logical symbols 3.1.1
        • Logical connectives
      • Strings of symbols 3.1.2
      • Types of propositions 3.1.3
        • Rules of inference
      • Formal theories 3.1.4
      • Expressions in an object language 3.1.5
      • Expressions in a metalanguage 3.1.6
    • Propositional and boolean logic 3.2
      • Propositional logic 3.2.1
      • Boolean logic 3.2.2
    • Predicate logic and relations 3.3
      • Predicate logic 3.3.1
      • Relations 3.3.2
  • Mathematical logic 4
    • Set theory 4.1
    • Metalogic 4.2
      • Proof theory 4.2.1
      • Model theory 4.2.2
    • Computability theory 4.3
  • Classical logic 5
  • Non-classical logic 6
    • Modal logic 6.1
  • Concepts of logic 7
  • History of logic 8
  • Literature about logic 9
    • Journals 9.1
    • Books 9.2
  • Logic organizations 10
  • Logicians 11
  • See also 12
  • External links 13

Foundations of logic

Philosophical logic

Philosophical logic

Informal logic and critical thinking

Informal logicCritical thinkingArgumentation theory

Deductive reasoning

Theories of deduction


  • Fallacy  (list) – incorrect argumentation in reasoning resulting in a misconception or presumption. By accident or design, fallacies may exploit emotional triggers in the listener or interlocutor (appeal to emotion), or take advantage of social relationships between people (e.g. argument from authority). 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

Symbols and strings of symbols

Logical symbols

Logical connectives

Logical connective

Strings of symbols

Types of propositions

Rules of inference

Rule of inference  (list)

Formal theories

Expressions in an object language

Expressions in a metalanguage

Propositional and boolean logic

Propositional logic

Boolean logic

Predicate logic and relations

Predicate logic


Mathematical logic

Mathematical logic

Set theory

Set theory  (list) –


Metalogic – The study of the metatheory of logic.

Proof theory

Proof theory – The study of deductive apparatus.

Model theory

Model theory – The study of interpretation of formal systems.

Computability theory

Computability theory – branch of mathematical logic that originated in the 1930s with the study of computable functions and Turing degrees. The field has grown to include the study of generalized computability and definability. The basic questions addressed by recursion theory are "What does it mean for a function from the natural numbers to themselves to be computable?" and "How can noncomputable functions be classified into a hierarchy based on their level of noncomputability?". The answers to these questions have led to a rich theory that is still being actively researched.

Classical logic

Classical logic

Non-classical logic

Non-classical logicDeviant logic

Modal logic

Modal logic

Concepts of logic

Mathematical logic

History of logic

Literature about logic



Logic organizations


See also

External links

  • Taxonomy of Logical Fallacies
  • An Introduction to Philosophical Logic, by Paul Newall, aimed at beginners
  • forall x: an introduction to formal logic, by P.D. Magnus, covers sentential and quantified logic
  • Translation Tips, by Peter Suber, for translating from English into logical notation
  • Math & Logic: The history of formal mathematical, logical, linguistic and methodological ideas. In The Dictionary of the History of Ideas.
  • Logic test Test your logic skills
  • Logic Self-Taught: A Workbook (originally prepared for on-line logic instruction)