I doubt, hence I am / Ich zweifle, also bin Ich / Duvido, logo Existo / Dudo, por lo tanto Soy

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, ...