The Three Classic Laws of Thought

The three classic laws of thought are attributed to Aristotle and are fundamental in the field of logic. The three laws are:

1. The law of identity, which states that a thing is identical with itself.
2. The law of noncontradiction, which states that two contradictory statements cannot be true at the same time.
3. The law of excluded middle, which states that, for any proposition, either the proposition is true or its negation is true.

The last two laws form the basis of the technique of reductio ad absurdum, as well as being fundamental to the study of propositional logic.