Doubt is the origin of wisdom
I can doubt everything, except one thing, and that is the very fact that I doubt. Simply put - I think, therefore I am
The first precept was never to accept a thing as true until I knew it as such without a single doubt.
I did not imitate the skeptics who doubt only for doubting's sake, and pretend to be always undecided; on the contrary, my whole intention was to arrive at a certainty, and to dig away the drift and the sand until I reached the rock or the clay beneath.
... moral certainty is certainty which is sufficient to regulate our behaviour, or which measures up to the certainty we have on matters relating to the conduct of life which we never normally doubt, though we know that it is possible, absolutely speaking, that they may be false.
