Rook: Establishing Independence of Sources, Mark, Luke, L, Matthew, M and Q
I've just finished reading Bart D. Ehrman's "Truth and Fiction in The Da Vinci Code" and found it to be a very enjoyable read.
A couple of things that I wanted to get your thoughts on are regarding establishing that sources are in fact independent, or draw on different sources to confirm the same event as historically likely.
Ehrman states that Mark is one source for Matthew and Luke because Matthew and Luke tell many of the same stories word for word (p 112-113). He goes on to state that certain claims made about early christianity are likely to be historically accurate because of various criteria (he briefly describes "the earlier the better", "piling on the testimonies", "cutting against the grain" and "context is (almost) everything" ). In "piling on the testimonies" he says that scholars are significantly helped when they find early sources that independently provide the same information about [jesus] because if they are independent then neither one of them could have made it up (p123). I'm fine with this, it makes sense to me.
However, he does go on to say that things like womens; roles in the early ministry (p147) are independently attested because they come from Mark and Luke's special source (L). So my first question is being that L is not available for us to examine, how can it be claimed that L is the most probable source rather than the Luke author simply copying Mark again, just not word for word this time?
Ehrman also seems to put forth the position that independent attestations that we already know about indicate and actual historical Jesus.
Yet he also stresses the point that there is no contemporary evidence for Jesus and the earliest written accounts came after decades of oral tradition and gave the example of the popular children's game of 'telephone' (which I knew as 'chinese whispers' when I was growing up). He points out that "Ultimately everything goes back to either a historical source or to someone who made things up" p101.
So my second question is, even if it can be shown that Matthew and Luke were using their special sources that no longer survive rather than rephrasing Mark for the purposes of their own historical context, how is it possible to claim with any reasonable degree of certainty (given the 'telephone effect' and lack of archaeological evidence) that their sources are ultimately a) independent and b) not coming from "someone who made things up"?
Ehrman states that most reliable sources we have for early Christianity, and hence Jesus, are the canonical gospels, but are their independence actually more well verified than what I have managed to glean from this book? Is lack of independence in accounts of Jesus part of your mythicist position?