See, there's a difference between knowing what you don't know and living in a sea of ambiguity the way the OP seems to imply. In mathematics especially, there is a very tall and elaborate edifice of deductions and axioms from which all exploration takes place.
For example, one of the more mind-bending exercises in undergrad abstract algebra is proving Peano's axioms for integers. On the one hand you could say "well, I thought I knew basic arithmetic, but now I have to question even that: I'm lost!" But on the other hand, when you go through that exercise, you have very powerful tools in your toolbox: deduction, group theory, ring theory, etc, which you spend time building up and exercising exhaustively before you attack the natural numbers. So you're not really "lost" as in at sea without a clue, but you're just approaching something from a new direction with very well-defined assumptions and rigid reasoning.
And if I can hope to contribute to the religious debate without sparking too big of a flame war: maybe this same conflation between being completely lost and working in an unfamility coordinate system may be at play when Skeptics and scientists describe why they're athiests. Empirical evidence and deductive reasoning can peel away some scripture as obviously false, but when you're denying a higher power by an appeal to logic/reason/etc, you're still assuming the presence of this abstract thing called mathematical/empirical truth, and perhaps even Order with a capital 'O'.
I'm sure I'm not at all speaking for any sort of majority view of believers or skeptics or deists, but why is it not valid to call that God and be comforted by its existence, as opposed to say chaos?