Back of the Envelope

The Evangelical Atheist argues that it's impossible to take the Bible to be partly literal and partly figurative:

If some passages (aside from the “literal figurative passages” previously mentioned) are taken as literal and others are not, one must be able to defend the distinction. When challenged to do so, these people offer a few typical responses. One is to imply that all of the self-contradictory parts are figurative. This is a convenient but baseless argument that works backward from a comfortable conclusion. Another response is to say that some of the miraculous passages are figurative because they couldn’t really have happened the way they’re written. However, which is more absurd: the resurrection or the burning bush? If any of the extraordinary portions are taken as literally true, this argument falls apart.

The main problem with this argument is that it takes an overly simplistic view of the Bible, as if it's a single book written by a single person, rather than a collection of 66 books, many of which, arguably including Genesis, are also collections of stories from different sources. Thus it makes sense to look at each book on its own, for what it claims to be, in order to decide if it's literal or figurative. The gospels claim to be eyewitness accounts of Jesus's life and ministries. They contain repeated refrains that this is either the account of witnesses or painstakingly researched (the end of John and the beginning of Luke, in particular). You may disagree, but if so, you have to conclude that the account is not just figurative, that it is inherently dishonest.

Some books can be taken either way. There can be disagreement over Job, for instance. Its poetic form, with the prologue and epilogue recounting events in Heaven, suggest a figurative account to some, while others see no reason to discount the events, even if they've been rendered into poetic form. The poetic dialogue may summarize the central arguments of a real debate among real people, even if they didn't speak in poetry at the time.

Genesis, if taken to be what the most literal interpretation of Divine Inspiration calls it, is God's description to Moses of his actions in history and relationship with his chosen people up to that moment. Others believe that it is a collection of the oral stories of the Israelites collected by Moses. Taken that way, these stories can be treated individually according to their genres, and the question of figurative or literal meaning dealt with for each story separately, not as a whole.

The creation account of Genesis 1 has some formulas which suggest a figurative meaning. The first three days consist of the creation of the kingdoms: light and dark on the first day, air and water on the second, and earth on the third. The second set of three days concern the creation of the rulers of those kingdoms: the sun and the moon on the fourth, the birds and the fish on the fifth, and animals and man on the sixth. Some Christians find this convincing evidence that the story is not meant literally, while others say that just because it follows a storytelling formula doesn't mean it didn't actually happen that way.

Thus I think the figurative vs. literal interpretation of each book has to be dealt with separately, and is often open for debate.