law of contradiction

American  

noun

Logic.

1. the law that a proposition cannot be both true and false or that a thing cannot both have and not have a given property.

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Example Sentences

See Examples For:

law of contradiction

The law of contradiction, after all, is not enforceable; if it were the jails would overflow.

From The Wall Street Journal ● Oct. 2, 2016

Of course, the past cannot be different from what it was, but no more can our present wishes be different from what they are; this again is merely the law of contradiction.

From Mysticism and Logic and Other Essays by Russell, Bertrand

God has to submit to the logical law of contradiction, and He cannot, according to the theologians, cause two and two to make either more or less than four.

From Tragic Sense Of Life by Flitch, J. E. Crawford (John Ernest Crawford)

Secondly, he has lost sight altogether of the other sense of Not-being, as the negative of Being; although he again and again recognizes the validity of the law of contradiction.

From Sophist by Plato

For example, the two propositions, 'this tree is a beech' and 'this tree is not a beech', are not coherent, because of the law of contradiction.

From The Problems of Philosophy by Russell, Bertrand