Today in the student Union, there was another "we lived with dinosaurs on our 8000 year old planet" person handing out booklets on why he thinks what he thinks. I'll spare you the details as I'm sure you already know the type I'm talking about. Keep in mind though, he wasn't hitting us over the head with his Bible, but simply following the conservative Christian view of Young Earth Creationism (YEC).
Now, politically, morally, and ethically I consider myself a "conservative" or "libertarian;" however, when it comes to Christianity I would label myself a "liberal" only because the conservative view seems to be a YEC-type view on Christianity. I thought I would pen my ideas on why I believe what I believe in the form of a response to the booklet this guy in the Union gave me (here's the website referenced on the back cover if you care to read this person's ideas more in-depth). Keep in mind that what follows is written by a Christian to another Christian.
First off, we'll start with a basic "ground rule" that (I hope) can all be agreed upon. This is that the Bible is the complete word of God written down by man. This gets contentious when determining if what the men wrote down was literally what God was saying or if he was saying something similar and through our own limited comprehension, got the message but not necessarily the exact words. I'm of the opinion that there are several parts of the Bible that are interpretive simply because the message is the more important lesson and not necessarily the logistics of said parts.
So, with the ground rule in place, let's get to the heart of the issue: is the book of Genesis to be taken literally or figuratively? I contend that it is to be interpreted figuratively for three reasons. First of these reasons is that other parts of the Bible are obviously figurative (such as Genesis 3 "they opened their eyes"). Secondly, there are instances in the New Testament where Jesus says things that are obviously false when taken literally, but are actually quite true when reading into what Jesus' message really was. Finally, since Genesis is the only book Moses did not personally experience, we are reading his interpretations of what God told him happened.
So first: Genesis is to be taken figuratively. I say this because of several parts in Genesis where it mentions Adam's privileges and rights. When God said to Adam he would have dominion over all the creatures, for example. Most people take that to mean that humankind as a whole has dominion over all the creatures (or at least just the males). Now if you take the literal interpretation, you have to believe that such a charge was given only to Adam and to nobody else. We could get into birthrights and monarchy debates, but you can read Locke's "Treatise on Two Governments" for a sound rejection of that logic.
My second example I point to as evidence of a figurative interpretation of the Bible is in Genesis 3.
7And the eyes of them both were opened, and they knew that they were naked; and they sewed fig leaves together, and made themselves aprons.
-Genesis 3:7 (KJV)
Now, for one who argues that Genesis is to be taken literally MUST, by the nature of their position, believe that Adam and Eve were literally blind until the 3rd chapter of Genesis. Very few people will take this stance and they will argue (correctly) that this means simply that they realized their own self-awareness. Of course, this chapter is also where we get original sin.
Next, there are examples where Jesus said things that would obviously be false when taken literally. For example, Matthew 17:20.
20And Jesus said unto them, "Because of your unbelief: for verily I say unto you, If ye have faith as a grain of mustard seed, ye shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you." -Matthew 17:20 (KJV)
I've never seen someone stand in front of the mountains and say "get out of my way" and the mountains moved. I could argue I've tried it myself and failed, but a sound rejection of that argument is easy ("well you just didn't have enough faith"). Since it's impossible to prove a negative, the onus is on the literal interpreter to show me that a mountain CAN be moved by faith alone simply by talking to it. Jesus' main point here was that through God, a believer can do amazing things which indeed is true. For example, the man who escaped a prison in China by walking out the front gate and boarding a plane for America using a passport that wasn't his and being honest with customs agents in both countries (they laughed thinking he was joking). I believe such miracles are possible. Another example is the spread of Christianity in hostile nations. Could a person witness to militant Muslims or deranged criminals without faith in God (as happened recently and whose name escapes me)?
Another example of Jesus speaking in figurative terms is his discussion with Nicodemus about being "born again."
2The same came to Jesus by night, and said unto him, Rabbi, we know that thou art a teacher come from God: for no man can do these miracles that thou doest, except God be with him.
3Jesus answered and said unto him, "Verily, verily, I say unto thee, except a man be born again, he cannot see the kingdom of God."
4Nicodemus saith unto him, how can a man be born when he is old? Can he enter the second time into his mother's womb, and be born?
-John 3: 2-4 (KJV)
Nicodemus picks up the obvious absurdity of what Jesus is saying here and Jesus goes on to explain himself that he is speaking about being born again in the spirit--not of the flesh. If anything, this is a perfect example of why a literal translation of the Bible doesn't always work and Jesus actually explicitly tells Nicodemus, only after he is confused, that Jesus explains what he meant by his words. Now suppose that Nicodemus did understand and John had not written down what Jesus meant. A literal interpretation of this passage would be that we would all have to crawl back into our mother's womb and come out again making salvation a messy (and weird) proposition.
I can extend this argument even further by pointing out that Jesus continually spoke in parables and his teaching method was to be an example, and use examples and allegories. Why is it so hard to believe God would not have done the same thing with Moses (or any other host of second-hand Biblical authors) in the book of Genesis?
Moses' account in Genesis was not directly witnessed by him (for the most part). In fact, the book is written to the point where Moses himself is leading the people out of Egypt. After that point, Moses was writing down accounts of himself and his exploits which I have an easier time taking literally.
Now, what are the implications of all this? If the universe really is 20 Billion years old, does that invalidate the Bible? I don't think so. As I mentioned above, Moses' interpretation of what God was actually saying changed from "first I did x, second I did y, etc." to "on the first day, God created..."
Also, a main argument in the booklet I was going to talk about was that when science disagrees with the Bible, we are to simply (and blindly) take the word of the Bible over the evidence we see based on the interpretation this book is advocating (literal). To me this is a dangerous position to take because blind faith and refusing to admit to being wrong leads to driving planes into buildings. It's also prideful for one holding this position because "it must be science... I couldn't possibly be wrong in my interpretation" is taking as fact that you're right because you're right, which is circular.
There are three possibilities here: first, that science is indeed wrong about the age of the universe and the literal interpretation is correct; second that the literal interpretation is wrong and the earth really is as old as science says it is; lastly that both the literal interpretation AND the scientific theories derived from the evidence so far is wrong. I'm inclined to believe that the latter of the three is the most likely given inherent problems in both theories (primarily evolution in the science aspect). Therefore, I don't believe a figurative interpretation of the Bible where a Christian can accept the age of the universe being 20 Billion years old, is in any way a conflict of scripture.
I feel this whole argument is missing the intent for which the Bible was created. It's like reading "Gulliver's Travels" and worrying about the validity of a man going to an island full of tiny people rather than capturing the underlying message the author hoped people would pick up; in this case, political satire. Likewise, people bicker about the details of the Bible when it's the underlying message that we should all heed.