The question of when Genesis was written is not a new one. It has been a focus of modern biblical scholarship since the eighteenth century. Unfortunately, this scholarly development is often looked on as largely negative, as if it is simply unsettling the undisturbed consensus of thousands of years of Jewish and Christian opinion. Modern biblical scholarship is hardly above criticism, and some dramatic shifts have happened that were unprecedented in the pre-modern period. But it is wrong to suggest that a universal and undisturbed consensus was suddenly under attack by academics. Modern scholarship on the Pentateuch did not come out of nowhere; the authorship of the Pentateuch as a whole had posed challenges to readers centuries before the modern period.
Having some insight into when the Pentateuch was written has helped readers today understand something of why it was written. That why question is important when the discussion turns to the relationship between Genesis and modern science—be it cosmology, geology, or biology. The more we understand what Genesis was designed to do by its author, the better position we will be in to assess how Genesis is or is not compatible with modern science. Making false assumptions about what to expect from Genesis is perhaps the single biggest obstacle to a fruitful discussion between science, especially evolution, and Christianity.
This essay is limited in scope. It is mainly a descriptive historical survey of some issues surrounding the question of when the Pentateuch was written and how that question was answered. There will always be some differences of opinion on how that question is answered specifically, but there is a strong, general consensus today among biblical scholars that is important to grapple with in trying to understand Genesis: the Pentateuch as we know it is the end product of a complex literary process—written, oral, or both—that did not come to a close until the exile (586-539 BC) and postexilic period. The Pentateuch as we know it is a response to the crisis of exile, and much of the Old Testament as a whole seems to be explained in a similar way. Understanding something of why we have a Bible at all will help Christian readers today think more theologically about how best to engage Genesis as God’s Word when the topic turns to the compatibility of Genesis and evolution.