Our guest today is Dr. Stephen Carlson of
Australian Catholic University. He is perhaps best-known to some
readers due to his 2012 dissertation (at
Duke University)
that featured a very detailed compilation of the book of Galatians. Dr.
Carlson, thank you for joining us.
SCC: Thank you, Jim, for your interest.
JSJ: You wrote a recent article that appeared in
the
Journal of Biblical Literature with a provocative title:
“A Bias
at the Heart of the Coherence-Based Genealogical Method.” Before we get to the article’s substance,
could you briefly explain the claims that advocates of the Coherence-Based
Genealogical Method have made about it? What
is the CBGM supposed to provide that we did not have before, and how?
SCC: The
basic claim of the advocates of the CGBM is that they have a “more rigorous”
way to evaluate external evidence in the textual criticism of the New Testament.
External evidence, your
readers may recall, is the weight we put on a particular variant
reading due to the manuscripts that record it. Prior to the CBGM, the usual way to deal
with external evidence is to sort them into text types like Alexandrian,
Western, and Byzantine, and then evaluate the external evidence based on how
well the text types support a particular variant reading. And the CBGM folks
are right that his approach is not sufficiently rigorous. Indeed, a big problem
with this traditional approach is contamination, where a manuscript may obtain
its readings from multiple sources. This makes
it difficult to define the various text types (the rise and fall of the
“Caesarean” text type in Mark is a good case in point) and hard to assign some
manuscript to a particular type when it has the characteristic readings of more
than one text type. In essence, the CBGM proposes to be more rigorous than this
by eschewing text types altogether and looking at relations between “potential
ancestors” of various manuscripts. In my article, I argue that the way that
potential ancestors are identified and even defined is fundamentally flawed and
we should look for other ways for evaluating the external evidence.
JSJ: The CBGM has a reputation for being complex
and inaccessible. But in your recent
article, you state that you have been able to implement its algorithms, and
that as a result, you noticed a problem.
Would it be accurate to say that you detected a built-in bias in the
“genealogical coherence” aspect of the C.B.G.M. as it currently exists?
SCC: Yes, I
detected a bias in how they identify genealogical coherence. In the CBGM genealogical
coherence comes from manuscripts having a common, extant “potential ancestor”
in their textual flows, and potential ancestors are identified on how much they
differ from the initial text. But distance from the initial text is not a valid
genealogical criterion and it can be misled by genealogically irrelevant data.
As a result, the CBGM is biased against bad copies of earlier texts
and in favor of good copies of later texts. Bias is a problem of course
because it distorts our ability to evaluate the external evidence and it gives
more weight to certain manuscripts (or less weight to others) than we would if
we knew the actual history of the text. The worst that can happen is that the
CBGM would give apparently strong support to a late, non-initial reading, especially where
the internal evidence is not decisive enough to countermand the misleading impression of the CBGM.
JSJ: Generally, it’s understandable to assume parsimony,
but random things sometimes happen that affect the text, such as having the
same scribal accident occasionally occur independently in different transmission-streams. How are these things handled? How many “accidental agreements” have to
occur before one says, “These agreements are not accidental”? Or to put it another way: could you explain the concept of coherence
and non-coherence?
SCC:
Accidental coincidence is a major problem. In fact, I think it is the most
underappreciated problem among New Testament textual critics (who tend to be
more worried about contamination). The CBGM does have an approach to accidental coincidence, which its proponents tend to call “multiple emergence.” Basically,
you look at all the manuscripts attesting a particular reading and sort them to
groups, so that each group is coherent (that is, having a textual flow that goes through a
common, potential ancestor). When the manuscripts are not coherent, they’ll be
in their own group. If you have multiple groups of such manuscripts, then you
have multiple emergence of the variant. Of course, if the CBGM is not able to
identify correctly that a group of manuscripts attesting the same reading is
actually coherent because of some bias, then the CBGM will wrongly subdivide
them into several groups and suggest that some readings are coincidental when
they are in fact not.
JSJ: Here’s a diagram [resembling Figure 4 in your
article] reconstructing a simple transmission-stream. In your article the flow is from left to
right; here, it is from top to bottom, waterfall-style. Can you tell us what this diagram is saying,
and what is wrong with this picture?
SCC: This
diagram is a simple stemma of a hypothetical history textual
transmission. The story here begins at the top with A, the initial text. Two
copies, B and X, are made of it, and B has one error, while X has two. (This is
represented in the diagram with a length between A and X being twice the length
of the branch between A and B.) Likewise, two copies, C and Y, are made of X,
with C being more error prone than Y. Similarly, two copies of made of Y, E and
D, with D more error prone than E. If we lose A, X, and Y, can we reconstruct
the true history of the text based on B, C, D, and E?
It turns
out that if we assume no contamination or coincidences, we can reconstruct
the history on the traditional “common-error” principle, but under the same
assumptions we cannot under the CBGM. The reason that the CBGM cannot reconstruct
the true history of the text under these very ideal condition is that it has a
bias that makes accidental coincidences between B and E look coherent when they
are not. And it
suggests that the variants that B and E carry are better than the ones carried
by C and D. For 1 John, these relations actually hold if you translate B to the
fourth-century 03 (B/Vaticanus), C to the fourth-century 01 (ℵ/Sinaiticus), D
to the fifth-century 02 (A/Alexandrinus), and E to the tenth-century 1739 (but
a very good copy of a much earlier text). So this simple stemma does not point
to a merely theoretical problem but an actual one in the transmission of 1
John.
JSJ: How realistic is it, in your opinion, to use
real-life manuscripts’ texts as proxies for potential ancestors of other
manuscripts’ text? Especially considering that we have a
relatively small representation of surviving manuscripts, and also considering
that no versional evidence and no patristic evidence is used in the CBGM?
SCC: It’s
only realistic within the Byzantine text and only if we look at a lot of them. Otherwise,
it’s not realistic at all. Outside of the Byzantine text, the manuscripts are
too few and too divergent
from each other to be good proxies for potential ancestors. Due to the bias at the heart
of the CBGM, the extent of these divergences are enough to make many of them
appear to be potential descendants of more carefully copied text, when they are
in fact cousins to varying degrees. Indeed the big problem with the potential
ancestor notion in the CBGM is that it assumes that all relations between
manuscripts can be characterized in terms of ancestors and descendants, instead
of siblings and cousins, which is vastly more common on the historical record
we actually possess. As for versional and patristic evidence, the CBGM does
not even look at them, and even if they did, they may be so incomplete that it could
yield nonsensical results (imagine if an Old Latin manuscript is a “potential
ancestor” of a Greek one?).
JSJ: Toward the end of your article, you pointed
out that the CBGM gives an unjustifiable level of weight to a combination of
witnesses – a combination that includes 1739 – in First John 1:7, where δε is
not included in the text of Nestle-Aland 28 even though its support is both
ancient and vast. Again: what’s wrong with this picture?
SCC:
This is the bias in action. The CBGM really likes 1739
due to its relatively short distance to the initial text. This means that every
reading it has—including its singular readings—is potentially the initial
reading even when every earlier text disagrees with it. This means that the
critic has to establish the text based solely on internal evidence, which is
notoriously difficult in cases involving “particles and articles” that don’t
really affect the propositional meaning or translation of the text. In the past,
textual critics didn’t think this external evidence was good enough to warrant
serious consideration; with the CBGM now they apparently do. I can only hope
that our ability to evaluate the internal evidence for more substantive variant
readings is good enough to overcome the CBGM’s bias.
JSJ: Let’s look at another textual variant that was
adopted in Nestle-Aland 28: the
Byzantine reading Πρεσβυτέρους τους at the beginning of First Peter 5:1. Vaticanus, Alexandrinus, P72 and 2412 read
Πρεσβυτέρους οὖν, Sinaiticus, Y, 623, and 1611 read
Πρεσβυτέρους οὐν τους, and 1505 simply supports Πρεσβυτέρους. I can see how internal arguments could lead
to the adoption of τους, but how does the CBGM get there? And how can one tell when the CBGM has had a
decisive role in decision-making in NA28, and when it was not a factor?
SCC: This variation
unit
is one of those
where the editors of the Editio
Critica Maior (ECM) changed their mind. In the first edition of the ECM for 1
Peter in 2000, they went with Πρεσβυτέρους οὖν with 03 (B, Vaticanus); but in the second edition of
the ECM in 2013, they went with
Πρεσβυτέρους τοὺς with 1739 instead. Now, 03
and 1739 are the two closest manuscripts to the initial text for the CBGM, so
their readings are always going to look good for the CBGM, particularly when
the Byzantine text agrees with them. Moreover, all the variants are coherent,
so there is little guidance on that front. Apparently, what happened is that that
the editors changed their mind on the internal evidence between the two
editions. Why they did so is unclear, and I cannot find any documentation or
commentary on this variant. The only clue I have are the local genealogies
published on Muenster’s institute’s website (
http://intf.uni-muenster.de/cbgm2/LocStem1.html ),
and they differ between the two editions. In any case, the external evidence is
effectively neutralized here under the CBGM and plays no important role.
JSJ: Do you think that the recent decision to
adopt μέρει in First Peter 4:16 was made primarily due to a rethinking of
internal considerations, and the CBGM was simply along for the ride? Mink’s argument (see p. 72 of Wasserman &
Gurry’s New Approach) sure sounds
like it was driven by internal evidence.
SCC: This variant gets a bit outside the scope of
my paper but it shows a different way that the bias at the heart of the CBGM
can pop up, but it takes some explaining. There are two readings in 1 Pet 4:16.
The older reading of the NA27 is “in this name” (ἐν τῷ ὀνόματι
τούτῳ) and is
supported by an all-star cast of P72, 01 (ℵ/Sinaiticus), 02 (A/Alexandrinus),
03 (B/Vaticanus), 044 (Ψ), 33, 81, 1611, 1739, Old Latins, Coptic, Syriac, Armenian,
Gothic, Ethiopian, and Cyril. The testimony of the earliest and most widespread
witnesses is unanimously in favor of “in this name.” And it makes good sense in
light of our knowledge of the earliest persecutions against Christians. The
newer reading in the NA28 is “in this respect” (ἐν τῷ μέρει
τούτῳ) is
entirely Byzantine (049, P, 104, 180, etc.).
It is important to note that the Byzantine text is not
monolithically in favor of the second reading: there are also quite a few
Byzantine manuscripts that have the “in this name” reading. In my research, this
is the result of contamination, because I have ways of connecting the Byzantine
manuscripts with this reading to older, non-Byzantine texts, but the bias of
the CBGM can’t find this contamination because its potential ancestor formula
is flawed. In fact, it gets the source relationships backwards, and is unable
to recognize the actual sources of the contamination. As a result, the user of
the CBGM is misled into thinking that going from “in this respect” to “in this
name” is a common, independent change, when in fact the opposite was actually
more common, to correct an older manuscript with “in this name” to “in this
respect” in conformance with the more common, contemporary Byzantine reading.
As a result, I strongly suspect that the CBGM results in this case have colored
the editors’ reassessment of the internal evidence, causing them to favor a
different sense of the transcriptional probabilities than their predecessors.
For a good internal analysis on the merits of the previous NA27 reading (“in
this name”) see Jarrett Knight’s article in JBL last year.
JSJ: I’ve gotten the impression that the more
rival readings there are in a particular variant-unit, the less useful the CBGM
becomes – downright chaotic – and the more unstable the Nestle-Aland
compilation is likely to become at those points. Have you gotten this impression, and if so,
why does this seem to be the case?
SCC: There is a big issue over
the size and scope of variation units that is largely ignored in our
discussions to date, so there isn’t much to go on. I suspect that, as in the
case of 1 Pet 5:1, when all the variants are coherent (which seems to be easier
to happen when there are more of them), then the CBGM does not have much to
offer the textual critic for decision. But I’ll need to look at a lot more of
them to be more confident.
JSJ: When I look at things like the diagram of the
textual flow for Second Peter 3:10 (on page 76 of Wasserman & Gurry’s A New Approach to Textual Criticism,
about the CBGM), it looks like the CBGM began by building a line of descent for
each set of rival variants in a specific variation-unit, and somewhere along
the line its focus shifted, from being about relationships of readings, to
something more concrete, involving relationships of manuscripts (or,
manuscripts’ texts). (See the diagrams
on pages 89-91, and then, on p. 105, “The global stemma for the Harklean Group
in the Catholic Letters.) I still don’t
quite grasp how that was done – how the global stemma was made without simply
ignoring some of the data. Could you explain
that in a little more detail?
SCC: The key thing to know about the global stemma
is that, aside from a few toy examples, it was never published or used to edit
the text in the ECM. I spent a lot of time trying to understand it and how it
relates to the textual flows, only to learn that it is still under development
and irrelevant to the text of the NA28. I recommend ignoring it until it is
actually implemented because it is still under development and who knows how it
can change. All I can say is that the portion of the global stemma published in
Wasserman & Gurry defies easy historical interpretation.
JSJ: Are there any other reasons to
approach the CBGM with caution?
SCC: Let me enumerate some of them.
(1) In addition
to its bias, we mentioned that the CBGM does not take into account versional
and patristic evidence, an important set of evidence for the early periods of
the text.
(2) The behavior
of the “connectivity parameter,” which we have not discussed, seems to be
affected by the sampling bias, so the number would have to be different in the
well-sampled Byzantine text than outside of it, but the CBGM has no provision
for this.
(3) Another issue
is that the method may be too beholden to what the editors think is the initial
text. For the ECM/NA28, the editors started with a subset of the NA27 for all
intents and purposes, but what if they started with the Byzantine or Codex
Bezae? At this point, it’s an open question.
(4) Further, I
suspect that the CBGM is not even finding contamination correctly (see above
for 1 Pet 4:16), but that is something under active research and a matter for a
different time.
(5) Finally, the
major problem I have with the ECM and the NA28 is that the editors have not
adequately explained their reasoning in all the places where they changed the
text. This is particularly important because the CBGM’s problems mean that the
external evidence will appear less decisive than it used to and put a lot more
pressure on getting the internal arguments right. Yet, when the internal
arguments are not documented, it forces people to assume it was the CBGM that
caused the change when it could have been something else. Fortunately, the
decisions leading to the Acts is better documented that the Catholics, but even
then I still want something even more thorough.
JSJ: Thank you for sharing your thoughts with us.
SCC: You’re
welcome. I hope my explanations are helpful to your readers.
