- This article uses forms of logical notation. For a concise description of the symbols used in this notation, see List of logic symbols.
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.
