The Independence of Passages vs. Books
Among the seven “independent” Gospels to which Ehrman’s ABSIG (Agreements Between Seven Independent Gospels) refer are the Gospel of Matthew and the Gospel of Mark.
A “basic aspect” of the life or death of Jesus is the claim that Jesus was crucified by the Romans. There is agreement between Matthew and Mark on this “basic aspect”:
And they [the soldiers] crucified him [Jesus], and divided his clothes among them, casting lots to decide what each should take. – Mark 15:24 (NRSV)
And when they [the soldiers of the governor] had crucified him [Jesus], they divided his clothes among themselves by casting lots; – Matthew 27:35 (NRSV)
According to Ehrman these are “independent” Gospels, so here we have an agreement between two “independent” Gospels on a basic aspect of the life or death of Jesus. Can we put this into the matrix diagram as an instance of agreement between at least these two Gospels? No. That would be a mistake.
The problem is that the author of Matthew used the Gospel of Mark as a primary source of information about Jesus. This passage in Chapter 27 of Matthew, as Ehrman would no doubt agree, was based on the passage about the crucifixion of Jesus in Chapter 15 of Mark. So, this passage in Matthew is DEPENDENT on the passage from Mark. Because of this dependency, the passage in Matthew does NOT provide any confirmation or corroboration of the passage in Mark. The author of Matthew got this information from reading the Gospel of Mark.
So when Ehrman claims that the Gospel of Matthew is an “independent” Gospel from the Gospel of Mark, this is misleading and confusing. Hundreds of verses in Matthew are based on verses from Mark. So, it is clear that much of the Gospel of Matthew IS dependent upon the Gospel of Mark. Ehrman is just pointing out that there are some verses and passages in Matthew that are NOT based on Mark, and which thus probably do not have a dependency on Mark. One CANNOT simply compare passages in Matthew and Mark and upon finding an agreement on a basic aspect of the life or death of Jesus, declare that Matthew has corroborated that basic aspect found in the Gospel of Mark.
What this means is that as a general rule, when one finds an agreement between two (or more) of the seven so-called “independent” Gospels, one must then ask a crucial question:
Are these PASSAGES independent of each other?
Because Ehrman uses the term “independent Gospels” in a way that allows for the Gospel of Matthew to be considered an “independent Gospel” in relation to the Gospel of Mark, such supposed independence is irrelevant when we examine individual passages from various Gospels.
But when we look for agreements between various Gospels concerning basic aspects of the life or death of Jesus, we are examining individual passages, not entire works or books. Therefore, any claim to the effect that one passage from one Gospel confirms or corroborates a passage from some other Gospel concerning a basic aspect of the life or death of Jesus, we need a JUSTIFICATION of the claim that the two PASSAGES in question are independent passages. The fact that the two passages are from so-called “independent” Gospels is irrelevant and does not answer the crucial question at issue.
Because Ehrman never bothered to offer one single passage from any of the so-called “independent” seven gospels, there was never an opportunity for him to JUSIFY the claim that one passage from one of the seven Gospels was independent from another analogous passage (about the same basic aspect of the life or death of Jesus) in another of the seven Gospels. But if Ehraman had produced forty or fifty passages, some from each of the seven Gospels, in order to make a strong case for his key premise (ABSIG), then he would have had to JUSTIFY many different claims about the independence of these passages from their analogues in the other Gospels.
We will soon see that this would be a rather daunting task, one that might well require multiple chapters of a book to accomplish.
The Logic of Independence
The concept of “independence” is more complex than it initially appears to be. So, let’s start with as simple an example as possible, and then work our way towards examples of greater complexity.
Ehrman puts very little effort into discussing the concept of “independence”, but the little that he does say about it has some very significant implications. It is worth taking a bit of time to think about the meaning of the word “independence” and what it implies.
Suppose that there are only two books in existence, and that these are the ONLY two books ever written (so far in human history): Book-A and Book-B.
One logical possibility is that the author of Book-B used Book-A as a source. In this case Book-B would be dependent on Book-A. The contents of Book-A are thus, in effect, a cause of the contents of Book-B, at least of part of the content of Book-B, so let’s represent this situation with an arrow going from A to B:
A–>B (B is dependent upon A)
Another logical possibility is that the author of Book-A used Book-B as a source. In this case Book-A would be dependent on Book-B. The contents of Book-B are thus, in effect, a cause of the contents of Book-A, at least of part of the content of Book-A, so let’s represent this situation with an arrow going from B to A:
A<–B (A is dependent upon B)
Another logical possibility, which is probably very rare in reality, is that it is BOTH the case that Book-A is dependent on Book-B AND Book-B is dependent on Book-A:
A<–>B (A is dependent on B AND B is dependent on A)
How could this be possible? Wouldn’t this involve circular causation? Actually this is possible if, for example, both books were being written in the same time period (say the same four-month period), and when the author of Book-A had completed the first half of Book-A (say at the end of the first two months), the author of Book-B obtained a copy of that half of Book-A and used it as a source for the second half of Book-B, and if when the author of Book-B completed the first half of Book-B (say at the end of the first two months), the author of Book-A obtained a copy of that half of Book-B and used it as a source for the second half of Book-A. In this way, it is possible for Book-A to have a dependency on Book-B while Book-B also has a dependency on Book-A.
If we limit ourselves to evaluating the indpendence of PASSAGES rather than BOOKS, then this third logical possibility becomes even more unlikely and remote, because it is very unlikely that two authors would be writing analogous passages in the same short time frame and also read each others partial drafts of the passage prior to completing the writting of their own passage (this might, however, happen with cheating on Essay exams at colleges!).
If we can establish that Book-B is NOT dependent on Book-A, does that mean that Book-B is independent from Book-A? I’m not sure. It depends on how we understand the meaning of “Book-B is NOTdependent on Book-A” and it depends on whether “independence” is a symmetrical relation.
If “Book-B is NOT dependent on Book-A” just means that the author of Book-B did not use Book-A as a source, then it does not follow from this claim that Book-B is independent from Book-A.
Suppose that the author of Book-B had read Book-C and used that book as a source. Suppose further that the author of Book-C had used Book-A as a source. In this way even though the author of Book-B did not use Book-A as a source (and perhaps never even set eyes on a copy of Book-A), the information that came from Book-C might have been obtained (by the author of Book-C) from Book-A.
This is a circumstance in which it might well make sense to say that “Book-B is NOT dependent on Book-A” (meaning that the author of Book-B did not read Book-A or copy from Book-A) and yet it could also be the case that “Book-B is NOT independent from Book-A” (meaning that some of the information in Book-B can be traced back to Book-A, via Book-C).
Of course, I specified earlier that Book-A and Book-B were the only two books in existence, so on that assumption there could be no Book-C to complicate matters.
However, even if there were NO OTHER BOOKS besides Book-A and Book-B, a similar complication could arise because information can be transferred verbally (e.g. by oral tradition). So, even in my super-simple imaginary world where there are only two books in existence, things can get complicated and confusing because there could be an oral tradition that transfers information from Book-A to the author of Book-B without the author ever laying eyes on a copy of Book-A. (The complexity is just getting started.)
Another problem is whether “independence” is a symmetrical relation. Equality is a symmetical relation. If X = Y, then it follows that Y = X. So, asserting that X = Y implies that Y = X. If “independence” is a symmetrical relation, then asserting that “Book-B is independent from Book-A” implies not only that “Book-B is NOT dependent on Book-A” but also that “Book-A is NOT dependent on Book-B”.
It is not necessary to resolve this question right now about whether “independence” is a symmetrical relation, because even if we decide that “independence” is not symmetical, we still need to determine whether there are any significant dependencies in ANY direction between various passages of the seven Gospels if and when somebody gets around to actually providing specific passages from these Gospels in order to support the key historical claim (ABSIG).
The complexity involved with establishing “independence” of sources grows rapidly as we increast the number of books or the number of passages in question.
Suppose that somebody produces four different passages from four of the seven “independent” Gospels, and suppose these four passages agree on a specific basic aspect of the life or death of Jesus. What are the various possible dependencies that need to be eliminated?
Let’s refer to the four passages as A, B, C, and D. In order to justify the claim that these four passages were independent of each other the following dependency claims would need to be shown to be false (or very improbable):
In short, one would need to argue against all twelve of these possible “dependence” relationships.
But we know that other books and other passages exist besides just these four passages, so even if one shows that none of these twelve depdency relationship exist, there are other possible dependencies that could still undermine the claim that these four passages are independent of each other.
For example, there might be another passage E from one of the remaining three Gospels, and these four passages that agree with each other might all be dependent upon passage E. In that case, there would be only ONE actual source of this information, and there would be NO CORROBORATION between the four passages that were put forward as evidence for (ABSIG).
If there are basic aspects of the life of Jesus that are allegedly agreed upon by five or six or seven different passages from different Gospels, then the possibilities for dependency relations are multiplied further. For five passages, there are 20 different possible dependencies (5 x 4 = 20) that must be ruled out. For six passages, there are 30 different possible dependencies (6 x 5 = 30) that must be ruled out. For seven passages, there are 42 different possible dependencies (7 x 6) that must be ruled out. This does not include the task of ruling out dependency relations with other passages outside of the passages that are presented as evidence.
I hope that this brief discussion of the concept and logic of “independence” shows that the claim that several passages from several Gospels are “independent” from each other is a claim that carries many significant implications, and thus involves a serious burden of proof that may require numerous arguments and justifications to support, none of which you will find in Chapter 3 of DJE, because Ehrman does not even begin the task of providing historical evidence.
Because Ehrman never put forward ANY passages from ANY of the seven “independent” Gospels as evidence in support of (ABSIG), he never had the opportunity to start building the necessary complex justifications required to show that such passages were in fact “independent” from each other.