As a follow up to my previous post I would now like to ask the question, 'must we interpret OT texts that are referred to in the NT the same was as the NT author?' This is a difficult question, but when placed in the larger framework of the interpretation of the New Testament use of the Old Testament, it becomes easier to handle.
When the NT cites an OT passage, are we required to say that the original meaning of the OT passage includes the sense given it by the NT author? In Three Views on the NT Use of the OT both Darrell Bock and Peter Enns (in my opinion) successfully argue, 'no.' One can think of Paul's usage of Genesis 13:14-16 in Galatians 3:16, 29. There he plays on the fact that 'zera (offspring) is a collective noun in the Hebrew interpreting the word in two different senses 13 verses apart. In Paul's cultural context this type of exegesis was acceptable. In ours it typically isn't. This doesn't in any way invalidate Paul's theological point, it's just that the way Paul argues and the way we might argue if we didn't have Galatians would probably be different due to different cultural settings.
Does this help us out in Romans 5? The difference between Paul's understanding of Adam as a literal historical figure and mine, which does not see him as a specific historical figure is not a question of exegetical method per se. I would suggest that the difference in outcome is based on my worldview inherent in my cultural setting. I live in the age of science, Paul didn't. That's not to say that Paul would have agreed with me if he lived today, he may or may not have, we'll never know. However, Paul's understanding of Adam as an actual person is grounded in his cultural setting as a Jew and this is part of the incarnational aspect of Scritpure. I'm not questioning the theological point Paul makes, I'm just suggesting that we are not bound to the exact form of argument, when the argument is steeped in a 1st century Jewish worldview. Similarly we're not bound to an identical method of usage of the Old Testament. We need to use the OT in a way that makes sense in our current cultural setting.
I was going to deal with the issue of inerrancy in relation to Romans 5 and not understanding Adam and Eve as literal people, but Jeremy Pierce has handled it wonderfully in his comment dated 9/22/2009 at 6:04pm. If you're interested in that issue I refer you there.