LINK: I'm pretty sure you can short-cut around problems of whether man can know as much as God (or, if you're atheist, everything there is to know) as discussed here by simply pointing out that there are two examples that pop up in philosophical literature about this: the Pocket Oracle and the Book of Life, each of which gives you a perfect description of all the true facts about the world over time. So clearly you can have all possible information available to you.
Except, of course, that you either have to accept the truth of the Book by fiat, or else you end up with the problem of induction (imagine a Book of Life with one error, or perhaps ten, to get an idea of how indistinguishable it'd be from one which was totally correct). So even if you (along with everyone else) reject Cartesian skepticism, there's still a perfectly good reason to think that people are operating with imperfect information.
Of course, it's worth pointing out that Christian propositions get around this problem precisely because we believe them to be true by fiat.