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}, 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}, 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.