In classical logic, the law of non-contradiction (LNC) (or the law of contradiction (PM) or the principle of non-contradiction (PNC), or the principle of contradiction) is the second of the three classic laws of thought. It states that contradictory statements cannot both be true in the same sense at the same time, e.g. the two propositions “A is B” and “A is not B” are mutually exclusive. (Wikipedia)
Let him who disbelieves [in the law of non-contradiction] be beaten and burned until he admits that to be beaten and burned is not the same thing as to not be beaten and burned.”
– Avicenna (980-1037) [Source: Apologetics 315]
This guy Avicenna certainly knows how to make a point.