I know it has been nearly two years since this discussion took place, but back to (part of) PiCo's original point: there is no recognition (at the time I write) in this article of R. E. Friedman's redating of the P source to Hezekiah's time.  The mistake in attributing the P source (the last half of Exodus, all of Leviticus, much of early Genesis, etc) to postexilic times has made hash of much of the secular (history-minded) Torah-interpretation that I grew up with, and I am grateful to Friedman for helping me set matters straight.  I'd like to see this article provide just a little more help to others who might be similarly grateful.   (talk)