A Few Words about being a Theoretician

[The following are the closing paragraphs from John Lumley’s lecture that he gave after being awarded the 1990 APS Fluid Dynamics Prize.]

“Some comments on turbulence,” Phys. Fluids A 4 (2), Feb. 1992, pp. 203-211. (link)

I would like to close with a few words about being a theoretician in the United States toward the close of the 20th century. The United States is a curiously unsympathetic environment for a theoretician, or any scientist interested in fundamental work. We have a sociocultural/historical myth with which those of us who were children here grew up, of egalitarianism, practicality, inventiveness. An American, in this myth, is a man who rolls up his sleeves and pitches in, solving the problem at hand in a clever, simple, practical way (often involving bailing wire and-a wad of chewing gum), usually saying over his shoulder that he does not hold with book learning. Edison is often suggested as an example. Many of our heroes had trouble in school. We tend to regard too much faith in what is written as being a foreign invention. In this environment, the theoretician is viewed with alarm, and felt to be irrelevant. He is regarded as impractical, pie in the sky. It does not help that any theoretician worth his salt can come up with several contradictory theories a day. He had a beautiful theory to explain yesterday’s data, but this morning it seems that those data were wrong; this afternoon he has a new theory to explain the new data. Who can trust a man like that?

Despite all that, theory is what gives meaning to observation. Understanding is the process of constructing simple models that explain the observations, and permit predictions. What the theoretician does is a vital part of the loop, and does not receive enough credit here. Our typical reaction to a theory is “let’s see some computations. How does that compare with the data?’ Those pragmatic questions are legitimate, and of course, any theory must rush to answer them. However, first the theory exists alone, as an entity in and of itself, and deserves to be appreciated on its own merits. Is it internally consistent, does it connect all the known behavior in a minimalist way? Does it patch smoothly to previously accepted theories? A theory that does all that in an effortless way is often called elegant. Tomorrow, it may be wrong. Even so, it deserves to be regarded as one of the better things of which man is capable.