Dem′on‐stra″tion (?), n. [L. demonstratio: cf. F. démonstration.] 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. Locke.
2. An expression, as of the feelings, by outward signs; a manifestation; a show.
Did your letters pierce the queen to any demonstration of grief? Shak.
Loyal demonstrations toward the prince. Prescott.
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.
Direct, orPositive, demonstration(Logic & Math.), one in which the correct conclusion is the immediate sequence of reasoning from axiomatic or established premises; — opposed to Indirect, orNegative, demonstration (called also reductio ad absurdum), in which the correct conclusion is an inference from the demonstration that any other hypothesis must be incorrect.