Comments on: Thinking about the end product

By: Leor

Leor — Mon, 30 Jan 2012 08:01:48 +0000

OK. What type of contamination are we discussing? From Tosefta, Amoraim? Before or after we’re assuming the Mishna was committed to writing? Some cases are going to be clear later additions, like at the ends of tractates, but many are going to be very difficult to identify. I’m hoping that your research will help identify more of those sections.
In any case, it seems that the majority of the Mishna could be analyzed with algorithms used for biological phenotyping. For example, sections which appear in all manuscript versions of the mishnah, but with significant orthographic variation. (and assuming that these variations do not appear verbatim in parallels, which might indicate contamination).
These sections (the majority) could be analyzed algorithmically and the “junk DNA” (l’havdil) could be thrown out. They will have to be analyzed separately using “higher” critical methods.

By: hlapin

hlapin — Fri, 27 Jan 2012 12:41:45 +0000

True, but the standard software packages do not make that assumption. It needs special processing as Desmond notes in his first comment.

By: Leor

Leor — Fri, 27 Jan 2012 07:27:28 +0000

Great site! — and the new format is much nicer. Yasher Koah!
So much to comment on, but related to what you’re discussing, I would question the assertion that text contamination has no biological parallel.
http://en.wikipedia.org/wiki/Horizontal_gene_transfer#Importance_in_evolution

By: hlapin

hlapin — Fri, 27 Jan 2012 00:46:33 +0000

Another comment from Desmond Schmidt. [and I’m tracking down the problem with “Error 1”.]

Taking the above idea further I’d like to propose for comment the following method. This is already somewhere in Greg’s Calculus of Variants, but I can’t remember where.
It seems that a basic stemma (NOT a phylogenetic tree) is an expression of literal similarities between versions. But textual traditions also contain: a) contaminations and b) lost manuscripts. Neither is modelled by biological software. These can be expressed mathematically by first computing the basic tree using an existing method, but based on *similarities* not differences. Then:
a) check for each pair of versions not directly related, whether their similarities differ from the corresponding reading of their common ancestor. Then they are contaminated.
b) If two versions both derived directly from the same ancestor share similarities that are different from the corresponding reading in the ancestor. Then we can postulate a lost MS as ancestor of both versions since the same mistake is unlikely to occur twice.
All of this can be easily computed from an MVD. It would be interesting to test this idea against an artificial tradition to verify that it is accurate.
Drawing the tree could then be done using a custom routine. Forget about biological software.

By: hlapin

hlapin — Thu, 26 Jan 2012 20:55:04 +0000

Commented by Hayim for Desmond Schmidt:

If I understand this rightly, even the cluster analysis method considers the text as a whole, rather than parts of it independently. That’s the key problem in constructing a phylogenetic tree of a set of texts that include contamination, since contamination isn’t part of the biological model of evolution (at least not between different species). So I can’t help thinking if computing sameness might be a better criterion than computing difference. Computing number of readings in common between two texts could likewise be expressed via a matrix and could be used to reconstruct a “contaminated” tree, that is, one with dotted lines joining branches. But it would need a different tree-building algorithm altogether.
The different results obtained by considering substantive and orthographic differences separately are interesting but it takes a lot of effort to subdivide the data this way, effort specific to a particular text. For a general method I’m not convinced that merging the two kinds of information together would produce anomalous results.