And if he is told that his claim...

And if he is told that his claim, although one hundred per cent correct, is also one hundred per cent wrong, would he accept it? Of course not. It is thus proven that the very claim that this principle is invalid proves its validity. It is clear that all those who have stated the view that contradic­tion is possible or necessary, either had some other meaning of "contradiction" in mind, or have not understood the meaning of the concept correctly.

Otherwise, the impossibility of contradiction-if its meaning is correctly understood-is…