On Mathematical Modeling and Inter-Disciplinary Work in Historical Linguistics: A Reply to Alexei Drummond—and a Friendly Critique of the Field

We would like to thank everyone who has posted comments on our recent posts on Indo-European linguistics, whether favorable or critical. As we have been highly critical ourselves, we can only expect the same in return; such is the give-and-take of the scholarly endeavor. We  will post detail replies to critical comments next week, after Asya Pereltsvaig returns from her travels. The present post responds only to the first comment posted on GeoCurrents by one of the co-authors of the Science article that we have taken to task. In that response, Alexei Drummond takes on some significant epistemological and methodological issues that demand a considered answer. As Drummond argues:

Personally I would love to include more direct evidence-based information into the computational analysis to correct the details (and see if that changes the main inference of the location of the origin), but that would require the linguists and archaeologists to actually embrace the value of computer models to synthesize large amounts of data. How can a human mind, however elegantly expressed its written conclusions, correctly balance the thousands of items of evidence to provide a probabilistic statement about history in a way that others can verify (i.e. The Horse, the Wheel and Language)? What is good about our approach is that the simplifying assumptions are clearly stated and can be improved upon in subsequent analyses. I just wish that the historical linguistics crowd would try *constructive* rather than destructive criticism for a change. We want what you want: to determine what happened. So as we are all scientists, we should work towards common ground, shouldn’t we?

Try as we might, we find little to disagree with in this eloquent appeal for the use of computational techniques and interdisciplinary research. As Asya Pereltsvaig has emphasized, we respect the work of linguists who use such methods in their own research. We advance no objections to computational methods per se, but rather to this specific application. Successful modeling cannot rest on unsubstantiated and most likely false assumptions about language spread and diversification, cannot disdain verification efforts, cannot be inherently unfalsifiable, and cannot be consistently contradicted by the empirical record. Drummond is surely right that well-crafted mathematical models can be continually adjusted to better fit the reality that they seek to represent—but only if they rest on solid foundation. Certainly the model under consideration could be sharpened, as has been suggested by another co-author, by incorporating elements of physical geography beyond the water/land dichotomy; such an improvement could weed out such blunders as having the Tocharians’ advance along 20,000-foot ridges while bypassing their eventual home in the Tarim basin. But as long as the model rests on the untenable assumption that languages spread through a contagion-like process and diverge in speciation-like events, the result will still be of little value. Subsequent posts will examine how languages do spread and change. As we shall see, such linguistic processes are vastly more complex than the scenarios posited by the Science team. That does not mean that they cannot be mathematical modeled, only that any such efforts will have be much more involved than what we have seen thus far.

We therefore hope that Alexei Drummond will continue to apply his formidable skills to the problems of language spread and diversification. We also hope that in the future he can collaborate not merely with other modelers, scholars whose skill sets overlap to a great extent, but also with experts with complementary skills and frameworks of knowledge. In particular, such work must be done with a bone fide Indo-Europeanist; collaborators with proficiency in world history, geography, and linguistics more generally would also prove highly beneficial.

Although is easy for us to dish out such advice, it would probably prove much more difficult for anyone to take it. As Drummond notes, it seems likely that many if not most historical linguists would rebuff any such invitations for collaboration. Here it becomes necessary for us reverse our critical attention and apply it to historical linguistics itself. Although this series of posts seeks to vindicate the field, we are convinced that a successful defense of any beleaguered intellectual enterprise demands a self-critical* eye.

Historical linguistics is currently in crisis not only because of unsubstantiated attacks or the failure of others to appreciate its intellectual achievements; it is also languishing because its practitioners have failed to meet the challenges that they face. All told, they have remained too insular and too comfortable with their own research paradigms. Emphasizing, like good scientists, the narrow acquisition of knowledge along established research fronts, few members of the guild have been willing to stand back and address the larger implications of their own work for the study of human pre-history (and history), let alone offer edification for a general audience. By the same token, few historical linguists have collaborated extensively with scholars in other disciplines. It is no accident that the three best-known scholars in the debate on Indo-European origins are (or were) all archeologists: Maria Gimbutas, Colin Renfrew, and David Anthony.

Historical linguists might reply that progress in linguistic research demands tightly focused inquiry and highly specialized disciplinary techniques, and would thereby gain little through interdisciplinary collaboration. Such arguments make sense when applied to specific issues, but collapse when it comes to broader matters, such as the origin of the Indo-European family, which is as much a matter of history and geography as it is of linguistics. And regardless of whatever intellectual arguments can be made for highly focused specialization, pragmatic considerations call for a different approach; it is a fact that historical linguistics is a diminishing field that has been unable to fend off mass-media celebrations of encroachments on its own terrain. If their field is to survive, historical linguists much realize that they can no longer be satisfied merely by communicating with each other. They not only must engage more with other scholars, but they must also reach out to the educated public.

Our charge is perhaps not as difficult as it might seem. The public is deeply interested in such issues, as attested by the articles in the popular press on the Bouckaert et al. paper. Asya and I have discovered the same interest while teaching on the intersection of linguistics, history, and geography in Stanford University’s Continuing Studies (adult education) Program, where our classes are consistently among the most popular offerings. Although we would like to think that our teaching skills have something to do with our enrollment numbers, we realize that they stem largely from demand for instruction on a topic that many people find intrinsically fascinating. Next winter, we will be teaching a class specifically on the geo-history of the world’s major language families. But in looking for a text that draws together the major issues within a single, comprehensible framework, we find ourselves frustrated. The best work that we have located thus far is a 1994 Scientific American article entitled, “World Linguistic Diversity,” by none other than archeologist Colin Renfrew. It is unfortunately short and somewhat dated, and it is almost certainly wrong on such major issues as the origin of Indo-European and the existence of Altaic. We do find it odd, and rather sad, that no comparable work has, to our knowledge, been produced by a historical linguist.

* “Self-criticism” is not the best term here, as neither of us is a historical linguist. I am a historical geographer and Asya Pereltsvaig is a linguist who specializes in syntax. What we thus offer is perhaps best described as “friendly criticism.”


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