One always begins with the simple, then comes the complex, and by superior enlightenment one often reverts in the end to the simple. Such is the course of human intelligence.
In dealing with the arrogant asserter of doubt, it is not the right method to tell him to stop doubting. It is rather the right method to tell him to go on doubting, to doubt a little more, to doubt every day newer and wilder things in the universe, until at last, by some strange enlightenment, he may begin to doubt himself.