Defn: 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.
DEMONSTRATIVE
De*mon"stra*tive, a. Etym: [F. démonstratif, L. demonstrativus.]
1. Having the nature of demonstration; tending to demonstrate; making evident; exhibiting clearly or conclusively. "Demonstrative figures." Dryden. An argument necessary and demonstrative. Hooker.
2. Expressing, or apt to express, much; displaying feeling or sentiment; as, her nature was demonstrative.
3. Consisting of eulogy or of invective. "Demonstrative eloquence." Blair. Demonstrative pronoun (Gram.), a pronoun distinctly designating that to which it refers.
DEMONSTRATIVE
De*mon"stra*tive, n. (Gram.)
Defn: A demonstrative pronoun; as, "this" and "that" are demonstratives.
DEMONSTRATIVELY
De*mon"stra*tive*ly, adv.
Defn: In a manner fitted to demonstrate; clearly; convincingly; forcibly.
DEMONSTRATIVENESS
De*mon"stra*tive*ness, n.