An Appreciation

Biology and Philosophy 13: 1–4, 1998. c 1998 Kluwer Academic Publishers. Printed in the Netherlands.

Tom Kuhn – An Appreciation PHILIP KITCHER Department of Philosophy University of California at San Diego La Jolla, CA 92093 U.S.A.

In the late 1960s, any aspiring British undergraduate looking to study the philosophy of science would have been told just where to go. Princeton was obviously the place, the academic home of C.G. (“Peter”) Hempel, wellknown as an extraordinary teacher and “the dean of philosophers of science” (the standard Cambridge description). But Hempel was by no means the only attraction. There was also T.S. Kuhn whose slender monograph, The Structure of Scientific Revolutions, published only a few years before, had already excited a wide-ranging discussion. Those who arrived at Princeton expecting to find Kuhn giving regular seminars on his controversial theses were destined for disappointment. To be sure, Kuhn was giving graduate courses, wonderful courses on the grand sweep of the history of western science up to the early modern period, but he was reluctant to offer the philosophy seminar to which his name was attached in the Princeton catalogue. According to popular rumor, he was unhappy with the cut-and-thrust of minute arguments, in a context in which his interlocutors seemed unsympathetic to his big ideas and entirely ignorant of the historical background to them. If the Kuhnian view was that advanced in SSR, then it seemed only possible to study it with him indirectly. That reticence was entirely typical of Kuhn’s attitude to his most famous book. Critics and would-be Kuhnians alike often found that he was unhappy with the theses ascribed to him. Now, more than three decades after the original publication, it is easy to understand why, to recognize how the making definite of ideas that were carefully balanced, delicately nuanced, and, sometimes, blurred could appear mistaken, even offensive. In the 1960s and 1970s, Kuhn was linked with Paul Feyerabend, and the two of them seemed intent on a form of irrationalism, the glorification of “mob rule” in science, the advocacy of relativism. Properly brought-up philosophers wanted none of it, and scores of analytically-trained graduate students sharpened their swords to attack the

2 dreadful dragons. Meanwhile, at the other end of the corridor, historians and sociologists were making a takeover bid of their own, apologizing for the passages in which Kuhn seemed to retreat from his most startling claims, and advertising themselves as Kuhnians (later as post-Kuhnians). Like Mercutio, Kuhn found himself in an extremely difficult position. Through the last decades of his life, he attempted to solve the problem in a variety of ways: returning to history, then collecting some extraordinarily rich and stimulating essays (The Essential Tension), writing a long-promised book on the early history of quantum theory, turning to analytic philosophy (after the move to MIT), and always struggling to rearticulate the doctrines of SSR. Many audiences have heard lectures, brilliant and provocative presentations, that went over Kuhn’s central themes from a variety of new perspectives, but he was not satisfied. Potential misinterpretations continued to haunt him, although he surely took comfort from Paul Hoyningen-Huene’s extended articulation and defense of his ideas. Everybody knows the central plot line of SSR. Science begins as preparadigm chaos gives way to the acceptance of a paradigm that defines a tradition of normal science. Normal science is primarily puzzle-solving, and the daily work of science tests the scientist, not the paradigm. Ultimately, one or more of the puzzles proves recalcitrant, becoming seen as an anomaly (or anomalies), and the field enters a state of crisis. Once again there is debate about fundamentals and the entrenched paradigm may conflict with proposed new paradigms. If one of these is accepted, then the resolution cannot be by the kinds of rules recorded in traditional logical empiricist philosophy of science. Proponents of different paradigms are at linguistic cross-purposes, they do not agree on their observations of the world, they make different value judgments about the importance of particular problems and achievements – they live in different worlds. After a change of paradigm, a revolution, the world changes, and although some things seem to be retained, there is no coherent direction of development. The growth of science is like the history of life, evolving without any obvious criterion of progress. In many ways it is a simple plot, and the simplicity is part of the explanation of the book’s enormous success. But only a part. As one reads and re-reads the individual sentences, there are always new resonances, suggestions of a thesis more complex than that one had attributed. Returning to the book again and again over the past twenty five years, I have never read it the same way twice – and that, too, is an important factor in its influence. We think we know where Kuhn stands, until we find him in a slightly different place. Those who condemn – or celebrate – Kuhn the irrationalist (to cite just one example) can find much material in Section XII, reading of “conversion experiences” and “decisions that can only be made on faith”, but then they reach the bottom of

3 p. 158 and a paragraph in which successive sentences seem to retract what has just been granted. There are many simple Kuhns, but they all turn out to be cartoons. So, reflecting on what scholars have done with SSR, it is hard to suppress a sense of embarrassment. The critiques of the 1960s and 1970s, which seemed once so powerful, appear flat and dated against the freshness of Kuhn’s own prose and the subtleties of his ideas. The enthusiasms of would-be Kuhnians are equally inadequate, often foisting on to him theses that are denied by his writings. In the end, there appear to be two possibilities. Perhaps there is simply no consistent position to be reconstructed; or perhaps SSR offers an insightful account of many aspects of scientific practice, an account that has been much misunderstood, and that Kuhn struggled to articulate more extensively. Whichever of these possibilities is the right one, Kuhn changed our world, the world of philosophy of science. Although his training in physics prompted him to gravitate to the physical sciences for inspiration and examples, there is no doubt that current work in the philosophy of biology draws on his ideas. Precisely because of the rich suggestiveness of SSR, I suspect that Kuhn will continue to be read long after the time at which virtually all the philosophy of the past decades is mouldering on the untouched stacks of library annexes – and that future scholars will continue to construct new Kuhns to embody their favorite (or least favorite) ideas. I want to close this brief essay with some words about Tom Kuhn, the man. The first thing that struck his students was the extraordinary energy: it seemed that the intensity of his thoughts had to find expression in the rapidfire delivery or in the vigorous gestures. Listening was immensely exciting, especially given the seriousness with which he took questions. Tom was also capable of great warmth and sympathy, able to reach out to people in trouble and to offer them support. (But for Tom’s efforts, I would never have gone to Princeton, and but for his support, among others’, I would never have been able to remain there.) Most vivid for me is the extraordinary intellectual honesty, the dedication to working things through and getting them right, so at odds with the facile relativisms often attributed to him. Tom was never convinced by the attractiveness of a solution generated in discussion. I recall numerous occasions on which, after an afternoon seminar or a strenuous discussion, he would call a temporary halt, insisting on his need to think the points over and then, the next day, he would come back with a new perspective, determined to continue the process. He must have known from his youth that it was easy for him to be clever. Being right was far harder – but only that was ultimately satisfying.

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Thomas Kuhn 19 –1996