Contradict

Demonstrate that a claim, hypothesis, theory, etc., is not true or that the opposite of it is true;

two claims contradict each other if one must be true when the other is false (and vice versa) – to say that two claims are contradictory is to say they are opposite claims: both could not be true at the same time nor could both be false or that it is impossible for both claims to be true or to be false.

(see also: contradiction, deny, refutation, reasoning, reasonableness»rational, critical thinking, falsification, argument, soundness, problem of adequacy, persuasion/persuasiveness, fallacy, reasoning, conclusion, claim, evidence, (hidden) assumptions, establish, support, ground, justification, controversies, reasonableness, critical thinking, falsification)