The CBGM in One (!) Sentence

The discussion from the post last week on Greg Lanier’s thoughts on the CBGM was helpful I thought. In particular, it made me think again about how best to present the CBGM to those who find themselves mystified and or even frustrated by its complexity.

In my experience, the most common reaction to the method is still mistrust and a kind of anxiety. Some of that is not surprising. We don’t like people messing with our New Testament text in ways we don’t understand. I get that. I get it because it was a major motivation for my own research. I wanted to know why my Greek New Testament was changing and whether the changes were any good. At its most basic, that was the reason for my dissertation.

In light of that, and in light of some of the feedback I’ve received from my JETS article, I wanted to follow up with a new attempt to explain the method. In particular, I want to take a stab at defining it in a way that is not only accurate and clear, but also somewhat less intimidating.

So here is my one-sentence description: the CBGM is a new set of computer-based tools for studying a new set of text-critical evidence based on a new principle for relating texts. (Notice that I have not used any of the words in the name “Coherence-Based Genealogical Method” to define it. My English teachers would be proud.)

I think that does a good job of covering all the bases. But it is still a mouthful, so let me try to explain each part in turn. I’ll start at the end and work my way back.

...based on a new principle for relating texts

This is not the CBGM.
(Although I kind of wish it was.)

First, the CBGM really is based on a new principle for relating texts. I say this because there has been some reasonable doubt (mostly from David Parker) about whether the CBGM really is a new method or actually just a new application of an old method, namely Lachmannian stemmatics. This was an early question in my viva, in fact. And for good reason, because right at the beginning of my thesis I had referred to the CBGM simply as a “tool,” a description I’ll come back to. But I am not convinced that the word “tool” does enough to cover what the CBGM is. So my answer to the question was (and is) that the CBGM is based on a genuinely new way to relate texts to each other. In particular, whereas Lachmannian methods deduce witness relationships based on shared agreement in “error,” the CBGM rather aggregates relationships based on both agreement and disagreement. That is, insofar as I know the history of TC, a genuinely new development. Certainly it has never been applied to the NT in this way before. I won’t go into the specifics here, because I’ve outlined the differences more in my JETS article. But suffice it to say that, at the heart of the CBGM, there is a genuinely new methodological principle for relating texts.

...for studying a new set of text-critical evidence

Second, along with a new method, the CBGM also provides us with a new set of evidence. That new type of evidence comes in the form of “coherence,” and it has two types or “flavors,” if you will. The first type is pre-genealogical coherence and it is new only in how it is used and how much data it uses. It’s not really new in terms of what it is. That’s because it is nothing more than a quantitative analysis of witness agreement. And that we’ve been doing for about one-hundred years in TC. What’s new is the amount of agreement used and, more importantly, how it’s used. It’s used to help us find possible (or less possible) relationships between variants. I won’t go into detail here, but a helpful example of how it works in practice is given in Tommy’s TC article on Mark 1.1 (PDF). The second type of evidence is very similar in function but much broader in terms of the data used. This type is called genealogical coherence (no pre- here) and this is a genuinely new type of evidence. At its simplest, genealogical coherence is used by taking all the data in the CBGM about witness relationships and then applying these data to specific textual variations. Looking at how the witnesses relate to each other overall can hopefully tell us something about how the variants themselves relate (or don’t relate) at the specific point we’re studying. In particular, it may suggest to us cases of “multiple emergence” or “coincidental agreement” of  reading, where scribes have independently created the same variant reading. For examples of using genealogical coherence, see the cases I cite in the appendix of my JETS article or read Tommy’s NovT article.

A new set of computer-based tools...

Third, this brings us to the CBGM as a set of tools. The reason my definition above leads with the word “tools” rather than, say, “method” is because this is how most of us will actually interact with and use it. That is, most of us will only really ever know the CBGM through the set of online tools known as “Genealogical Queries.” Right now, these are available for the Catholic Epistles but soon, we hope, for Acts too. The first version for the Catholic Epistles has actually been online since 2008. So these are “new,” but relatively so. There are five tools in particular. Two are for viewing information about possible witness relations. These are the “Potential Ancestors and Descendants” tool and the “Comparison of Witnesses” tool. There are two tools for studying the new type of evidence I mentioned above and these are aptly if not obviously named “Coherence in Attestations” and “Coherence at Variant Passages.” You can use both of these for studying the genealogical coherence at a specific point of variation. Unfortunately, there is currently no easy way to study pre-genealogical coherence at specific variations, except in the Gospels. But explaining that would take us too far afield. The last tool is simply called “Local Stemmata” and this will show you how the editors of the ECM/NA28/UBS5 have related nearly all the variants in the Catholic Epistles to each other. It’s quite amazing actually that we have this level of detail available. You won’t get any commentary, of course, but you will learn more about the editor’s judgment from these stemmata than you ever could just by looking at your NA or UBS apparatus.

So that’s it in nutshell. The CBGM is (1) a new set of computer-based tools for studying (2) a new set of text-critical evidence based on (3) a new principle for relating texts.

That’s it.

Okay, that’s not really it. There’s more to explain, especially about how to actually use these new tools. But hopefully this three-part way of defining the CBGM can go some way toward de-mystifying what I know can be an intimidating new development in our discipline. If it does that, then it will have done what it needs to do.

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As an addendum, I should say that I don’t know whether the teams in Münster or Birmingham or Wuppertal who are or will be using the CBGM would agree with all I’ve said. I obviously don’t speak for them. But this is my attempt after three years of thinking about it (almost!) every day to distill it for the “rest of us.” If others can do better than I have here, that’s great.