Is your knowledge that certain, and if so, how? If not, why not? What is it that you know with certainty? That you know through and through; that is as real to you as your being. What if everything you believe is wrong? Can you even admit that possibility?
Doubting leads to curiosity, leads to investigation, leads to insight, leads to more doubting. I like to be in a state of wonder, and questioning what is going on around me helps me get to that state. Besides enjoying the process, it helps me become more aware of what makes me tick, and of what is up with this World.
It is not the uncertainties that are too many, but the doubts that are too few.
I doubt that I doubt, therefore I confirm that I am. I doubt that I doubt, therefore, I doubt that I am. I doubt that I doubt, therefore, I am, independent of any doubting.