How Can We Know Who Wrote the Bible?

People are people and writers are writers. Whether they lived in 500 BCE or today. There is nothing magical or mysterious about the writing process. Once we accept that empirical fact and treat the stories as stories written by humans like us, we can glean a lot of information about the writers and the world they inhabited when they wrote their biblical stories.

Each writer, biblical or otherwise, writes in their own way. Everytime they write, they can only do so from their own perspective, inner world and the reality around them, using preferred words and expressions. There is no other way to write. Once we identify the style, perspective and favorite expressions that appear in a particular story, we can find real actual biblical writers that we know existed, and see if there is one with an identical style, perspective and word choice.

Just like films made in the 1930s are different from films made in the 1990s or today, so are biblical stories. Stories reflect a perspective on what is going on in the world at that time. This is true in stories set in the past, present or future, if they're realistic stories or include magic - they're always a perspective on the reality at the time of writing.

Here are the important periods in Hebrew history, which are all distinct and generate distinctly different stories (I rounded out the dates for convenience):

         1. 900 BCE - 600 BCE: the Assyrian period. The kingdom of Israel was destroyed and 

              Israelites immigrated to Judea.

         2. 600 BCE - 550 BCE: the Babylonian period. Judea and Jerusalem are destroyed and 

             thousands are taken captive to Babylonia, while others immigrate en masse to Egypt.

         3. 550 BCE - 320 BCE: the Persian period. After chaotic centuries, the Persians usher in

             an era of peace and harmony. Thousands of Hebrews return home to Judea.

         4. 320 BCE - 170 BCE: the Hellenistic period: Alexander the Great conquers the ancient 

              world, and Hellenism becomes widespread and popular.

         5. 170 BCE - 63 BCE: the Maccabean period: following an uprising, a civil war and a war of 

              independence, Judea is its own state again. Until the Romans come in.

In each of these periods, the Biblical writers were concerned with different things and had different values. Hebrew culture, like all cultures, never ceased to evolve and adapt to its time.

Around 150 years ago, scholars were able to identify the different layers in the first biblical books. These layers were sown together in editing to form the Bible we have today. Scholars named this finding the Documentary Hypothesis, and it allows us to read each of those layers in its own succesion, as it was written before the final editing. 

This allows us to know, for example, that the person who wrote about God sealing a pact with Abraham in Genesis is the same person who wrote about God reaffirming the pact with Moses in Exodus.

Below you can see which writers we have definitively identified so far.