Let's talk a little more about the current controversy over evolution. Some Christians will say: "Look, you can't pick and choose the parts of the Holy Scripture that you want to take literally. And so, if you're going to call into question the literalness of some parts, you inherently call into question the literal truth of it all." So how do you, as a scientist and a Christian, respond to that line of reasoning?
It's a good question. And certainly, as a believer, I would be the last one to argue that we can basically dilute and water down the Bible any old way we want to, to make ourselves feel better. That's certainly not a good approach to faith, lest one end up with something that doesn't resemble the great truths of the faith at all. But let's admit that down through the centuries, serious believers - long before there was any On the Origin of Species to threaten their perspective - had a great deal of difficulty understanding what some parts of the Old Testament, particularly Genesis, were really all about. The whole area of hermeneutics - the effort to try to read Scripture in a way that represents, as best one can, what the real meaning was intended to be - requires more sophistication than simply saying the most literal interpretation of every verse has to be correct.
One can look at Genesis 1-2, for instance, and see that there is not just one but two stories of the creation of humanity, and those stories do not quite agree with each other. That alone ought to be reason enough to argue that the literal interpretation of every verse, in isolation from the rest of the Bible, can't really be correct. Otherwise, the Bible is contradicting itself.
I take great comfort looking back through time, particularly at the writings of Augustine, who was obsessed by trying to understand Genesis and wrote no less than five books about it. Augustine ultimately concluded that no human being really was going to be able to interpret the meaning of the creation story. Certainly Augustine would have argued that the current ultra-literal interpretations that lead to young earth creationism are not required by the text, and would have warned that such a rigid interpretation, regardless of what other evidence comes to the scene, could potentially be quite dangerous to the faith, in that it would make believers out to be narrow-minded and potentially subject to ridicule. And in a certain way, that warning has come true with the battles we're having right now.
If Augustine, who was one of the most thoughtful, original thinkers about biblical interpretation that we've ever had, was unable to figure out what Genesis meant 1,600 years ago, why should we today insist that we know what it means, particularly when the interpretation chosen contradicts a wide variety of data that God has given us the chance to discover through science.