Brian LePort recently wrote about whether we can be confident that the author of Luke's Gospel was Greek. I made a couple comments about Brian's post on James McGrath's FB wall which I thought I'd share here.
Before I do, let me clarify my interest. I have little direct interest in the question of the author's ethnicity. Rather, my interest is 1) the question of how we might go about addressing such a matter and 2) the indirect relationship between the authorship and the date of any given NT book. The former relates to my work in my forthcoming volume from T&T Clark, The Quest for the Historical Jesus after the Demise of Authenticity: Toward a Critical Realist Philosophy of History in Jesus Studies, the latter relates to my decade-old obsession with the dates of the NT books, which seems to finally be coming together in a publishable form. With those interests defined, let me proceed to copy out what I wrote on James's wall, with some modifications for this context.
It strikes me that either Luke is what we might call a "Judaizing Gentile" or he's a "Hellenizing Jew." (And yes, both terms admit a possibility of nuance, but we're working heuristically here so we can allow a degree of fuzziness). Either he's a non-Jewish person (quite possibly but not certainly Greek) who is immersed in Jewish literature, or he's a Jewish person who is immersed in Hellenistic literature. Philo and perhaps to a lesser extent Josephus would probably both be in the latter category, but not the former. The artifacts (texts included) produced by the Judaizing Gentile are probably going to look much like those produced by the Hellenizing Jew, making differentiation between them difficult, but in terms of the historical dynamics at work they're going to be the result of nearly opposite movements (which happen to converge at very close if not quite identical points). Given the difficulties involved in categorizing texts as the product of an author of one category versus an author from the other I'm not sure if internal or comparative evidence is going to suffice. As such we might well have to advert to what data we have about the author from external material, and when it comes to Luke that is not nothing.
The best data is going to be that which is as contemporaneous to Luke's Gospel as possible. That end, let us examine first-century and early-second century Christian materials to see what they say about a figure named “Luke.” Interestingly, we find that there is such a figure referenced in the Pauline corpus (cf. Col. 4:14; 2 Tim. 4:11; Phlm. 24; possibly Rom. 16:21, but here we have Λούκιος rather that Λουκᾶς, and I’d guess that these are not intended to be the same figure). There are a host of clues in Colossians, 2 Timothy, and Philemon that lead me to think that these are all referring to the same figure, most notably the triangular relationship that is drawn between Paul, Luke, and certain other figures. Even granted that the authorship of Colossians and 2 Timothy are disputed the way in which early recipients of the Pauline tradition understood this figure “Luke” nonetheless stands as data for our purposes. And it is Col. 4:14 that is most interesting, because on the basis of 4:11 we have good reason to think that either Paul knew his companion Luke to be a Gentile or early Pauline interpreters knew him to be a Gentile. What we seem to be left with then is a situation in which there is only one figure known in first (or at latest, early-second) as “Luke,” and this figure is identified in the data as not-Jewish.
Now, let’s think through the possibilities that result from this judgment. If we judge that it was written by the Luke mentioned in the Pauline corpus (which I don’t think the data allows us to exclude) then we could be fairly certain that the author was not-Jewish. If we judge that it was attributed pseudonymously to this Luke, either when it was first written or secondarily, then we could be fairly certain that it was attributed to someone who was remembered as being not-Jewish, and thus his not-Jewishness quite reasonably can be construed as part of the fiction involved in the attribution. Both possibilities would seem to militate towards a not-Jewish authorship, at least more so than against. If we judge that the attribution has nothing to do with the one first-century Christian named “Luke” who was significant enough to appear in our data then we had best have strong arguments, as we are now going to run up against some significant issues of parsimony. As such, given the first-century data, it seems that a Gentile with a fairly high degree of immersion in Jewish literature remains the best judgment on the matter.
Thus far what I wrote previously. I would add the following. In response to the above it was suggested that this argument is speculative. I suspect that my interlocutor meant "hypothetical," to which I would simply respond "Yes," but I will take the word as it stands. And against that word I would suggest that the argument is not speculative but rather analytical. It makes a series of judgments on questions that arise as we seek to answer the initial question "Was Luke Jewish or Greek?" These judgments are given warrant by appeal to data. Evaluative criteria such as parsimony and (unspoken but implicit throughout) explanatory scope are invoked. The final judgment might be mistaken, but that would be not because it is speculative but rather because either error is made in the analysis or currently unavailable data obviates the analysis.