Deductive reasoning is the process of reasoning from the general to the specific. Deductive reasoning is supported by deductive logic, for example:

From general propositions:

  • All ravens are black birds.
  • For every action, there is an equal and opposite reaction
To specific propositions such as:
  • This bird is a raven, therefore it is black.
  • This billiard ball will move when struck with a cue.

In contrast to inductive reasoning, the conclusions of deductive reasoning are as valid as the initial assumption.

Deductive reasoning was first described by the ancient Greek philosophers such as Aristotle.

See also