RogueMonk pointed out in a comment to my original post that "a study of scripture that is guided by Christain conviction is completely safe because [we believe] it it is firmly held in the hand of a sovereign God." This is an important corrective to my statement that reading Scripture is not a safe enterprise. Nevertheless, it remains true that a careful reading will lead--for some people on some occasions--to questions that deal with issues which are central to faith.
Because careful historical study and the reading of Scripture is not a safe enterprise (see part 1), I may at some point reevaluate certain of the convictions about the world that I now take as given. For this reason, I reject the claim that as a believer my historical study of the Bible requires affirmative answers.
However, I don't surrender hold on my deepest convictions whenever I read the Bible or enter into a historical question. We can't start from scratch as Descartes tried to do--not, at least, if we want to retain our sanity. My commitment to the historic Christian tradition means that I affirm the resurrection and the virgin birth, though I lisp at the Creed's "descended into hell." This commitment has as much to do with my own past experiences as it does with an examination of the evidence. This is not unreasonable, for in practice we consider our basic convictions warranted by experience as well as intellectual reflection.
So while reexamining and sometimes changing working assumptions about the world happens from time to time, to abandon my faith (μὴ γένοιτο!) would be to undergo a paradigm shift of the first magnitude. Historical criticism alone wouldn't lead me there. That is because the historical-critical method is not well-suited to address these reasonable but non-rational assumptions that form the basis of our world-views--assumptions, however varied, that are a part of the world-views of atheist and theist alike. Historical criticism is not well-suited, that is, to deal with what Leander Keck calls "self-involving truth claims"--the claims whose acceptance means the transformation of a world-view.
Another weakness of historical criticism is also one of its greatest strengths: It allows for conversation. This means, on the one hand, that I am limited in the reasons I can give for specific arguments in certain conversations. Because not everyone shares it, I cannot argue for a particular interpretation on the basis of the resurrection, though my whole life is shaped by it. On the other hand, in very many topics careful reading (whatever we label it) allows for conversation with and the opportunity to learn from all sorts of people.