What to do if someone doubts the principle of contradiction?

What to do? :confused:

You can kick him with your foot and then allege that perhaps you have not kicked him.

Tell him you’re glad he doesn’t doubt the principle because it would be nonsense to do so, then take him to the state fair.

Ha! I liked that.

You could of course agree with everything the person says until they get so sick of it that they contradict you just for the sake of it.