I just finished reading your book Genesis, Science & History. Being a bit of a Bible nerd, I of course enjoyed it and learned some things, too. There are a couple of things I would like to share with you regarding my study of Genesis. Like yourself, I also once held to the day-age theory, and later, to the literary theory. Recently, I was exposed to still another interpretation. Though I am not completely convinced about it, it is perhaps the best interpretation I have come across yet. This interpretation is found in Genesis Unbound: A Proactive New Look at the Creation Account, by John Sailhammer. According to Sailhammer, Genesis 1:1 describes the creation of the whole universe, but from 1:2 on, the creation account is only concerned with the Promised Land. He identifies the Garden of Eden with the Promised Land. The phrase rendered "formless and void" indicates that the Promised Land was a desolate wasteland unfit for human habitation. In six literal days, God transforms this land into a land flowing with milk and honey, now filled with every plant and animal useful for man. If this is correct, this would fit the context of Genesis and the rest of the Bible very well. First, it fits into the context of the Books of Moses -- the land that was given to Israel. Second, it fits the Biblical theme of redemption -- God takes something that is worthless, and through His power and grace, transforms it into something wonderful. Third, it predicts the rebellion of the Jewish people. Just as Adam and Eve broke God's Law, and were driven from the land to the East, so Judah broke God's Law, and were also driven from the land to the East -- to Babylon. The following idea does not come from Sailhammer, but is my own, and it has to do with the long life spans of Adam and his near descendants. What I am about to say sounds weird, but I think it has a great deal of explanatory power. I am not at all convinced it is correct, but I do think it is interesting to ponder. What if mankind had already evolved on the earth, but the Genesis account of the creation of Adam and Eve is literally correct? That is, you have the so-called "natural" man that evolved, and you also have Adam and Eve who were specially created by God. Since Adam and Eve were designed by a perfect Designer, rather than the product of natural evolution, they would be physically perfect. That is, their genes wouldn't have all of the defects that are found in natural man. They would be genetically engineered to be resistant to heart disease and cancer, age well, etc. If Adam and Eve did have specially engineered genes, then it would explain their longevity. It would also explain why their descendants could intermarry without genetic concerns. Suppose, over time, that the descendants of Adam intermingled with natural man. Over time, defective genes would be introduced, gradually lowering the life spans of their descendants, thus explaining why the age of his descendants slowly, gradually decline until you reach normal life spans. This would explain why it was so important for the godly line to marry within the family. This could also explain why Sarah was considered so beautiful even at such an old age -- she aged well and looked much younger than her actual age. -- Steve Robertson

I think Sailhammer is on to something, esp. with respect to the Israelites becoming "landless," consigned to the East (Babylon). To understand ha-'arets as the land of promise, as opposed to the whole earth, is not a ridiculous idea, though it does seem to me to be too restricted. Perhaps he is right in that this is part of what the Genesis writer is saying. 

As for longevities and specially created humans, this seems unlikely. Why bother to bring hominids all the way to the point of humanity by means of evolution, and then specially create Adam? I think you have to argue for one or the other.