Deductive reasoning

Deductive reasoning, also deductive logic, logical deduction is the process of reasoning from one or more statements (premises) to reach a logically certain conclusion.

It differs from inductive reasoning and abductive reasoning.

Description

Deductive reasoning links premises with conclusions.

If all premises are true, the terms are clear, and the rules of deductive logic are followed, then the conclusion reached is necessarily true.

Deductive versus inductive

Deductive reasoning (top-down logic) contrasts with inductive reasoning (bottom-up logic) in the following way:

• In deductive reasoning, a conclusion is reached reductively by applying general rules that hold over the entirety of a closed domain of discourse, narrowing the range under consideration until only the conclusion(s) is left.

• In inductive reasoning, the conclusion is reached by generalizing or extrapolating from specific cases to general rules, i.e., there is epistemic uncertainty.

However, the inductive reasoning mentioned here is not the same as induction used in mathematical proofs – mathematical induction is actually a form of deductive reasoning.

See also

• Abductive reasoning
• Analogical reasoning
• Argument (logic)
• Correspondence theory of truth
• Decision making
• Decision theory
• Defeasible reasoning
• Fallacy
• Fault Tree Analysis
• Geometry
• Hypothetico-deductive method
• Inductive reasoning
• Inference
• Inquiry
• Logic
• Logic and rationality
• Logical consequence
• Mathematical induction
• Mathematical logic
• Natural deduction
• Peirce's theory of deductive reasoning
• Problem solving
• Propositional calculus
• Reason
• Retroductive reasoning
• Scientific method
• Soundness
• Syllogism
• Theory of justification

External links

• Deductive reasoning @ Wikipedia