Demonstration n. 1.The act of demonstrating; an exhibition; proof; especially, proof beyond the possibility of doubt; indubitable evidence, to the senses or reason. "Those intervening ideas which serve to show the agreement of any two others are called "proofs;" and where agreement or disagreement is by this means plainly and clearly perceived, it is called demonstration."
2.An expression, as of the feelings, by outward signs; a manifestation; a show. See also sense 7 for a more specific related meaning. "Did your letters pierce the queen to any demonstration of grief?" "Loyal demonstrations toward the prince."
3.(Anat.) The exhibition and explanation of a dissection or other anatomical preparation.
4.(Mil.) a decisive exhibition of force, or a movement indicating an attack.
5.(Logic) The act of proving by the syllogistic process, or the proof itself.
6.(Math.) A course of reasoning showing that a certain result is a necessary consequence of assumed premises; these premises being definitions, axioms, and previously established propositions.
7.A public gathering of people to express some sentiment or feelings by explicit means, such as picketing, parading, carrying signs or shouting, usually in favor of or opposed to some action of government or of a business.
8.The act of showing how a certain device, machine or product operates, or how a procedure is performed; usually done for the purpose of inducing prospective customers to buy a product; as, a demonstration of the simple operation of a microwave oven.
Direct demonstration, or Positive demonstration, (Logic & Math.), one in which the correct conclusion is the immediate sequence of reasoning from axiomatic or established premises; opposed to
Indirect demonstration, or Negative demonstration (called also reductio ad absurdum), in which the correct conclusion is an inference from the demonstration that any other hypothesis must be incorrect.
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