# Logic
|  | **Logic** is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the science of deductively valid inferences or logical truths. It studies how conclusions follow from premises due to the structure of arguments alone, independent of their topic and content. Informal logic is associated with informal fallacies, critical thinking, and argumentation theory. It examines arguments expressed in natural language while formal logic uses formal language. When used as a countable noun, the term "a logic" refers to a logical formal system that articulates a proof system. Logic plays a central role in many fields, such as philosophy, mathematics, computer science, and linguistics. |
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| | wikipedia:: [Logic](https://en.wikipedia.org/wiki/Logic) |
Contra [[Rhetoric]], [[Sophism]]
## [[Propositional calculus]] (Sentential, Zeroth-order logic)
- [[Deductive Logic]]
- [[Validity (logic)]] vs [[Soundness]]
- [[Necessity and Sufficiency]]
- [[Principle of Bivalence]]
- [[Tautology]]
- [[Truth Table]]
- [[Fallacy|Fallacies]]
- [[Natural Deduction]]
- [[Argument]]
### [[Rule of inference|Rules of inference]]
- [[Syllogism]]
- [[Mathematical proof]]
- [[Contraposition]]
- [[Inverse (logic)]]
- [[Converse (logic)]]
- [[Negation]]
- [[Reductio ad absurdum]]
## [[First-order logic|Predicate logic]] (First-order Logic)
- [[First-order logic|Predicate logic]]
- [[Intension]] and [[Extension]]
## [[Mathematical Logic]] (Symbolic Logic)
- [[Mathematical Logic]]
- Set theory
## Inductive, Abductive, Inferential, Fuzzy Logic, & Non-bivalent Logic
- [[Principle of Bivalence|Bivalence]]
- [[Inductive Logic]]
- [[Abductive Reasoning]]
- [[Inference]]
- [[Fuzzy Logic]]
- [[Many-valued Logic]]
- [[Probability]]
- [[Statistics]]
- [[Heuristic]]
- [[Mu (negative)]]
- [[Binary opposition]]
## [[Critical thinking]]
- [[Doxastic logic]]
- [[Burden of Proof]]
- [[Logic Puzzles]]
- [[Law of Thought]]
## [[Recursion]]
[[Mereology]]
## Inbox
- [[Argumentation Theory]]
- [[Rhetoric]]
- [[Persuasion]]
- [[Corollary]]
- [[Defeasible Reasoning]]
- [[Analogy]]
- [[Logical Consequence]]
- [[Logic and Rationality]]
- [[Logic and Dialectic]]
- [[Dialectical Logic]]
- [[Begging the Question]]
- [[Correlation does not imply causation]]
- [[Analytic Philosophy]]
- [[Process of elimination]]
- [[Argument from ignorance|Absence of evidence]] is not [[Evidence of absence]]
- [[Counterfactual]]