axioms, which are known as The Three Fundamental Laws of Thought.

(1) The Law of Identity--

Whatever is, is;

or, in a more precise form,

Every A is A.

(2) The Law of Contradiction--

Nothing can both be and not be;
Nothing can be A and not A.

(3) The Law of Excluded Middle--

Everything must either be or not be;
Everything is either A or not A.

26. Each of these principles is independent and self-evident.

27. If it were possible for the law of identity to be violated, no
violation of the law of contradiction would necessarily ensue: for a
thing might then be something else, without being itself at the same
time, which latter is what the law of contradiction militates
against. Neither would the law of excluded middle be infringed. For,
on the supposition, a thing would be something else, whereas all that
the law of excluded middle demands is that it should either be itself
or not. A would in this case adopt the alternative of being not A.