Thomas Brodie has shown that the theory that the Gospel narratives began as oral traditions is not founded on valid logical argument. Nonetheless, he recognizes that an idea that rests on little more than mere presumption “may still be useful as a working hypothesis.” So he proceeds to explore whether the theory of oral tradition works in New Testament studies. What follows is from Brodie’s chapter 6 of The Birthing the New Testament — all posts archived here.
First, here’s a chart of the arguments attempting to explain how oral tradition worked — as covered by Brodie. He covers many scholars in quick succession and it can be a bit numbing for someone wanting a quick blog read and who is unfamiliar with the topic to take it all in very easily. I use the many colourful images that have arise in the various attempts to explain how oral tradition is supposed to work: