I've been reading N. David Mermin's Boojums All the Way Through, a collection of his essays, articles, and book reviews. One of the book reviews is of a biography of Lev Landau, and one of the nuggets that Mermin extracts for the reader is Landau's logarithmic scale for rating physicists. Einstein apparently received a special rating of 0.5, while the (other) founders of quantum mechanics (Bohr, Heisenberg, Schroedinger) rate a 1. Landau apparently gave himself a 2.5 but later upgraded this to 2. Mermin, later in his book, describes himself as a 4.5. Landau apparently referred to physicists who rate a 5 (the worst score on his scale) "pathologists".
Reading about Landau's rating system has caused me to reflect on creativity in science. After all, what is it that distinguishes a 1 (or even a 0.5!) from a 5 in Landau's scale? I would argue that it is most certainly creativity. It surely is not hard work, for though the great physicists were passionate about there subject and thus undoubtedly worked quite hard I am certain that many who have worked as hard or harder still rate but a 5. It cannot be anything like mathematical ability. Einstein's self-reported troubles with math are well-known, and Bohr was apparently wretched at doing serious calculation. I suppose one might site physical intuition as the determining factor, but what exactly does that mean? Physics professors usually mean by "physical intuition" a certain level of internalizing of the known laws of physics. But the great physicists were great specifically because their thinking was NOT limited by an internalization of the known laws. They were able to see beyond what was known. I don't know what else to call this but creativity.
Creativity is an issue that has been much on my mind as I study the philosophy of science. Philosophers of science tend to ignore the creative aspect of science. I think this is for two reasons. First of all, philosophy of science is most often an attempt to rationally reconstruct the actual activities of science. How can one rationally reconstruct an act of creativity? Second, philosophers of science tend to focus on how scientific theories are tested and how the decision to modify a theory comes about. They focus much less on how new theories are constructed or how old theories are modified. The point of the philosophy of science is not so much to explain how scientists construct theories as it is to explain how we can make sure those theories are legitimate (or useful, or not blatantly wrong, or not entirely metaphysical). The creative act of science is thus outside the purview of philosophy of science. The main exception I can think of would be the early inductivists, who saw theories as generalizations from the data. But I don't think anyone would seriously argue that, even when such generalizations do occur (and I think they occur infrequently), this process is straightforward or simple.
But even if philosophers of science can't explain scientific creativity, is it possible to classify it in some way? It seems to me that scientific creativity is much like creativity in other areas. I'd like to draw some comparisons between physics and literature to illustrate this point. Let me make clear at the outset that I am no expert on English literature, and I am largely ignorant of non-English literature. But hopefully if I stick to things that I have read and that I know are widely acclaimed, I'll muddle through this without offending anyone.
Most of science is performed by people who are creative only on a small scale, in a somewhat workaday fashion. These would be Landau's 5's (I would rank myself among them, if I deemed myself worthy of any rank at all). Creating new scientific knowledge of any kind requires a certain level of creativity, in that you are doing something that has not been done before and therefore you cannot follow any sort of template. Probably most of the creativity actually comes in formulating a question to study, or at least choosing some investigation to perform (I rarely have a well-formulated question when I begin my research, but I usually do have some idea of something into which I want to poke my nose). Starting a research project involves a suite of choices that cannot usually be guided by established principles. In any field of science there are an infinite number of factors that can be analyzed, or relations that can be investigated. For most scientists the creative act comes in choosing which of these infinite possibilities will be productive or interesting. From that point on the work may involve only well-trodden pathways. I think this is something like most popular fiction. The author must come up with an idea for a novel or story, and if they are to avoid charges of plagiarism it must be an idea that is new on some level. But the typical work of popular fiction is pretty similar to something that has gone before, and both the prose and the literary conceits are likely to be standard fare. If Landau had rated novelists he would probably consider most authors on the NY Times Bestseller list to be "pathologists".
Somewhere much farther up the chain come those who extend the boundaries of the field in a significant way. This can be done by breaking new ground, or by finding hitherto unknown connections between disparate areas. In physics this might include those like Dirac or Feynman, who worked within the framework of quantum mechanics but extended that framework into new and unexpected territories (Poincare would be a similar example in the realm of classical physics). For an old school example, Johannes Kepler might fall into this category since we worked within a framework established by Copernicus but made a crucial extension (to elliptical orbits) that turned out to make all the difference. The great unifiers would also fit in this category (here I am thinking mainly of Weinberg, Glashow, and Salam for their unification of electromagnetic and weak interactions, but classical physicists like Lagrange and Hamilton might also fit this category, as might James Clerk Maxwell). In my limited knowledge of literature I would put Vladimir Nabokov in this category. Lolita was not, really, an entirely new type of novel. But it was about things that no novel had been about before. Similarly, Pale Fire turns a poem (and its exegesis) into a novel and thereby creates a connection that had not been exploited before. Note that this categorization deals only with creativity. Dirac and Feynman both possessed incredible technical prowess in addition to their creativity. Similarly, Nabokov's prose is nothing short of breathtaking. Perhaps it is impossible to separate these attributes from creativity, but I am at least not explicitly taking them into account here.
At or near the top of the creativity scale are those who change the face of their fields forever. In physics this would include Landau's 1's: Bohr, Heisenberg, Schroedinger. I'd add Boltzmann and Faraday. To go way back we could add Galileo and Copernicus in this category. These people gave us a new way of understanding the natural world. They had the vision to see far beyond the existing theories, and the courage and creativity to construct something radically new. I suppose Joyce would be in this category for literature (though I must confess that I have only read Portrait of the Artist as a Young Man, and parts of Dubliners - I'll get to Ulysses someday soon, but I may not be strong enough for Finnegan's Wake). I'd like to put Borges in this category as well (you see, I have read some non-English authors) because I think his creativity merits it, even if his prose does not (but then, I didn't read his work in Spanish so I can't really say). These authors wrote works that departed radically from the conventions of the day, and literature has not been the same since.
Now, what about that special case of Landau's: Albert Einstein, who merits a 1/2. I would argue that Isaac Newton merits the same special score. What author could merit such a special distinction? William Shakespeare? Fyodor Dostoyevsky? (OK, I admit that I'm trying to atone for my English-language leanings here.) I will let others more literate than I make that call. What is it that sets these people apart from the 1's? Again, I believe it is creativity but it is a level of creativity that inspires awe. The work of a 5 may lead one to think "I would have thought of that if I had worked on that problem." The work of, say, a 2 might lead on to think "I wish I could have thought of that, but I doubt I would have." In the case of the 1's, we might think "I can't believe they thought of that, they are geniuses." For those in this special category our thoughts are mute and we are left to gaze in awe at a mind that operates on a level entirely different from our own.
I'll close this essay by pointing out some interesting features of what I have just written. It strikes me as curious that all of the physicists I mention are theorists, not experimentalists (except Galileo and Faraday, who were both). The authors I mention are all prose authors (well, except Shakespeare). The second fact follows directly from my own personal prejudices (I prefer prose to poetry), which in turn have influenced what I have read. But the exclusion of experimentalists seems odd to me in retrospect, and it would be false to claim that I am simply unaware of highly creative experimental work. Millikan was incredibly creative, as was Michelson. James Joule certainly deserves some high marks for his creativity in studying the relation between heat and mechanical energy. In fact, I think one could argue that in recent years experimentalists have demonstrated a higher level of creativity than have theorists. But somehow this seems like a different type of creativity. For one thing, it is highly constrained creativity in that experiments must make use of apparatus that either exists or can be built with a reasonable investment of time and money. Theoretical creativity is largely free from such practical constraints. Furthermore, experimental greatness requires a set of skills that are not specifically intellectual. Perhaps one day I will write an essay comparing the great experimental physicists to the great painters. Could I, then, rate da Vinci in the same category as himself? Probably not - he was much better as a painter than as an experimental physicist, although this was probably not due to a lack of creativity. Anyway, until I write that essay I will simply apologize to the experimentalists and try to redirect the blame toward Lev Landau who got me started thinking about all of this anyway.
Saturday, October 6, 2007
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