Mind thine own concerns. If he believes not as thou believest, it is a proof that thou believest not as he believes, and there is no earthly power can determine between you.

You believe that you believe, but you don’t believe.

If I am not what you say I am, then you are not who you think you are.

Don’t believe anything I’ve told you — merely because I said it.

So try to be wrong.
Try to disprove your beliefs.
Never believe something on faith.
Prove it or disprove it.
While other people have one idea that they think might work, you will have thousands you can prove didn’t work, and one you couldn’t make fail.

What has shaken me is not that you lied to me, but that I no longer believe you.

Believe nothing, no matter who said it, even if I said it, unless it agrees with your own reason and common sense

Don't believe everything you think.

If I find some reason for doubt in each of my beliefs, that will be enough to reject all of them.

What is the proof that I know something? Most certainly not my saying I know it.

If our opponent believes nothing of divine revelation, there is no longer any means of proving the articles of faith by reasoning, but only of answering his objections — if he has any — against faith. Since faith rests upon infallible truth, and since the contrary of a truth can never be demonstrated, it is clear that the arguments brought against faith cannot be demonstrations, but are difficulties that can be answered.

if you can’t prove something wrong, you can’t really prove it right either.

I show you doubt, to prove that faith exists.

If the evidence says you’re wrong, you don’t have the right theory. You change the theory, not the evidence.