How do people use the Bible?

I've been looking at the Bible a bit as part of this little toy project I'm doing, and I ran across this line about Cush (pretty close to a common bastardization of my name), who begat Nimrod. Nimrod, it turns out, was the builder of the Tower of Babel in his career prior to being a Green Day album.

I made an offhand remark about how the Tower of Babel was used by the religious right as justification for squashing science and knowledge in areas like stem cell research, thus prolonging human suffering in the process. Catherine decided I was a condescending prick (which I often am), but on this particular point I'm still not convinced. In particular, Catherine, ever the well-studied philosophical relativist, argues that the Bible is a philosophical source like any other, say Plato, and that people who quote it are citing parables as analogies, finding eloquent statements of their own views, and finding views that have stood the test of time. She thinks the Bible has first principles no less indefensible than, say, utilitarianism, and that even arguing that my liberal views permit greater freedom by not trying to repress the behavior of others (something Lisa was recently discussing on her xanga and which I tried to convince Eric of recently) still relies on arbitrary principles. All this may be true, but I guess the real issue is the authority of the Bible. If the Bible is just plain wrong in places, then there is no real reason to believe any particular portion of the Bible unless there is specific reasoning backing it up. Unfortunately, the justification of any given idea may derive from God, of whom we have no existence proof and to whom, therefore, it is hard to ascribe any authority. Plus God is also the source of some of the wrong (slavery, subjugation of women, homosexuality) portions of the Bible. A lot of people, from what I've seen, quote the Bible not because it states something well, but because they think there is inherent authority in any precept of the Bible, even if no substantive justification is provided therein. I feel like somebody must have articulated my argument more clearly than me, but I'm way too lazy to find it.