Déductif

Déductif is a French adjective used to describe reasoning or approaches that derive specific conclusions from general principles or axioms. The term stems from the verb déduire (to deduce) and the noun déduction, ultimately tracing back to Latin deductivus. In French, déductif is commonly used to characterize methods, arguments, or styles that proceed by deduction rather than induction or observation.

In logic, deduction is a process where the conclusion follows necessarily from the premises if the argument is valid. Deductive validity means that if the premises are true, the conclusion cannot be false. A classic example is: All humans are mortal; Socrates is a human; therefore Socrates is mortal. Deduction yields conclusions guaranteed by the premises, provided the reasoning is sound.

In mathematics and philosophy, the déductif method refers to proving theorems by formal deduction from axioms and previously established results. This contrasts with inductive methods that infer general laws from observed cases. In scientific practice, a deductive approach uses hypotheses to derive testable predictions that experiments may confirm or refute.

In everyday use, déductif can describe a reasoning style or a narration organized around deduction rather than exploration, and it appears in discussions of logic, education, and linguistics where rules and generalizations guide analysis.