Deductive Reasoning

See: Deductive Reasoning Process, Deductive Logic.

References

• (Wikipedia, 2009) http://en.wikipedia.org/wiki/Deductive_reasoning
  • Deductive reasoning, sometimes called deductive logic, is [reasoning] which constructs or evaluates deductive [Argument (logic)|argument]s.
    In [logic], an argument is said to be deductive when the truth of the conclusion is purported to follow necessarily or be a [logical consequence] of the [premise]s and (consequently) its [corresponding conditional] is a necessary truth. Deductive arguments are said to be [valid] or invalid, never true or false. A deductive argument is valid [if and only if] the truth of the conclusion actually does follow necessarily (or is indeed a [logical consequence] of) the premises and (consequently) its [corresponding conditional] is a necessary truth. If a deductive argument is not valid then it is invalid. A valid deductive argument with true premises is said to be sound; a deductive argument which is invalid or has one or more false premises or both is said to be not sound (unsound).
  • An example of a deductive argument and hence of deductive reasoning:
    • All men are mortal
    • Socrates is a man
    • ([Therefore],) Socrates is mortal
  • Deductive reasoning is sometimes contrasted with [inductive reasoning].