Doubt is not a pleasant condition, but certainty is absurd.
Doubt is the key to knowledge.
Doubt is uncomfortable, certainty is ridiculous.
Doubt makes the mountain which faith can move.
Dubito ergo cogito; cogito ergo sum.
He who knows nothing, doubts nothing.
I doubt, therefore I think; I think therefore I am.
I think we ought always to entertain our opinions with some measure of doubt. I shouldn't wish people dogmatically to believe any philosophy, not even mine.
If you would be a real seeker after truth, it is necessary that at least once in your life you doubt, as far as possible, all things.
Love and doubt have never been on speaking terms.
Our doubts are traitors and make us lose the good we oft might win, by fearing to attempt.
The whole problem with the world is that fools and fanatics are always so certain of themselves, but wiser people so full of doubts.
There is nothing more dreadful than the habit of doubt. Doubt separates people. It is a poison that disintegrates friendships and breaks up pleasant relations. It is a thorn that irritates and hurts; it is a sword that kills.
When in doubt, don't.
When in doubt, tell the truth.
