Tautology

We know that any preposition has a value of true or false. Assume p is a proposition:

Since one of the two statements has to be correct we know the above is true without knowing what p is. We therefore say that the above statement is a tautology. It is impossible for it to be false. (See also Contradiction)

Appendix A

Let’s write a lie.

p = cats are herbivores

The value of p is false.

The value of is true.