deductive

First recorded in 1640–50, deductive is from the Latin word dēductīvus derivative. See deduct, -ive

Deductive and inductive refer to two distinct logical processes. Deductive reasoning is a logical process in which a conclusion drawn from a set of premises contains no more information than the premises taken collectively. All dogs are animals; this is a dog; therefore, this is an animal: The truth of the conclusion is dependent only on the method. All men are apes; this is a man; therefore, this is an ape: The conclusion is logically true, although the premise is absurd. Inductive reasoning is a logical process in which a conclusion is proposed that contains more information than the observations or experience on which it is based. Every crow ever seen was black; all crows are black: The truth of the conclusion is verifiable only in terms of future experience and certainty is attainable only if all possible instances have been examined. In the example, there is no certainty that a white crow will not be found tomorrow, although past experience would make such an occurrence seem unlikely.