Before Thomas Kuhn published The Structure of Scientific Revolutions in 1962, revolutions were supposed to epitomize what is objective about scientific inquiry: the rational revision of beliefs, even the most fundamental beliefs, in the face of better evidence. For Kuhn, however, a revolution was "a displacement of the conceptual network through which scientists view the world"¨a change not only in scientific theory and fact, but also in the very language of science, the methodology, and even what counts as a scientific fact. Scientists who live through a revolution find themselves, not merely working with a different theory, but living in a different world, with no objective grounds for comparison with the one they left behind. Outside of the philosophy of science, especially in the humanities and social sciences, Kuhn's view found an eager audience, for it seemed to say something that there was a widespread desire to hear: that science is not epistemically privileged over other disciplines, and has no special claim to objective knowledge; a scientific way of looking at the world is just another way of looking at the world, and therefore epistemically no different from other human belief-systems. And in the broader intellectual pop culture, "paradigm-shift" was added to the store of all-purpose buzzwords. But in the philosophy of science, this relativist interpretation of Kuhn was not generally accepted¨certainly not by Kuhn himself. Yet the challenge remained to digest the implications of Kuhn's work for the nature and the historical development of scientific knowledge, a project that became the major preoccupation of the philosophy of science for the remainder of the 20th century. The essays, lectures, and interview collected in The Road Since Structure represent Kuhn's own contribution to that project.
A book with such a title raises two expectations, only one of which is disappointed. First, one might expect to learn, simply, what Kuhn was up to between the appearance of his famous book and his death in 1996: what were his continuing philosophical preoccupations? How did he assess the impact of the book on the history and philosophy of science, on intellectuals in general, and on his own career? How did he react to the extremes of adulation and criticism that his book provoked? The essays collected in this volume go a long way toward answering these questions. Some of them have been well known for decades, such as "Reflections on my Critics", Kuhn's response to antagonists such as Karl Popper and Imre Lakatos, "establishment" philosophers of science who saw themselves as defending the rationality of science against Kuhn's irrationalism and relativism. The more recent essays respond, for the most part, to friendlier criticism, coming from philosophers who share some elements of Kuhn's perspective: that science has more historical and social dimensions, and that theory and observation have a more intimate and complicated relationship than philosophy of science had formerly acknowledged. Kuhn's engagements with these critics are correspondingly compromising, emphasizing his conviction that science is, after all, a "rational pursuit of knowledge," and that "what it produces is knowledge of nature"¨his struggle was to explain this fact, without resorting to what he saw as traditional myths or oversimplifications about science.
The most illuminating part of the book is "A Discussion with Thomas S. Kuhn", the 1995 "autobiographical interview" with philosophers Aristides Baltas, Kostas Gavroglu, and Vassiliki Kindi, which covers everything from Kuhn's early education to his last philosophical projects. It is an invaluable source of insight into the philosophical background of The Structure of Scientific Revolutions: his education as a physicist, his growing interest in philosophy, and the confrontation with the history of science that disturbed his assumptions about physics and philosophy. Kuhn also discusses his surprise at the radical interpretations of his book, especially the emergence of radical relativism and constructivism. Perhaps it was inevitable that Kuhn's account of the "paradigm" as defining a "form of life" for a community, and of "paradigm-shifts" as more like "conversions" than rational revisions of belief, would encourage the view of scientific knowledge as essentially a social construction and scientific truth as relative to the internal standards of a community. But Kuhn generally found himself replying, "But I didn't say that!" What he did say is that a scientific theory is essentially a language that "carves up"the world in a particular way, that different scientific theories carve up the world in radically "incommensurable" ways, and that believers in competing theories face an insurmountable problem of translation¨something like the problem that he himself faced as a 20th century physicist struggling, at the beginning of his historical studies, to see the physical world as conceived by Aristotle. To understand scientific revolutions, he concluded, is to abandon the notion that science changes continuously and that knowledge grows cumulatively. But what notions ought to replace these was not so clear to Kuhn in 1962.
One might therefore expect this book to answer another sort of question: what sort of coherent philosophy of science finally arose out of the ideas in Structure? If radical relativism or constructivism was not what he had in mind, then what was? The full answer to this question was supposed to take the form of a completely new book that Kuhn, unfortunately, did not live to finish. The absence of that book may be especially felt by readers of this one, some of whom at least will find it frustrating and tedious to read numerous scattered repetitions of the same interesting suggestions about scientific change¨as language-change, as social change, and as something akin to biological speciation¨with little development beyond mere suggestion, and in no particular order. (An index would have been helpful.) The biological analogy¨that science undergoes something like Darwinian evolution, including adaptation, extinction, and speciation¨was, on Kuhn's own account, the most interesting possibility, and an essential piece of the picture of science that he was trying to develop at the end. But this general idea is almost as old as Darwin's theory, and supports a wide range of opinions on the epistemological issues with which Kuhn was concerned, including the naive realism that he especially foreswore. It was even a staple of 19th-century positivism, as well as of its 20th-century successor, logical empiricism¨the philosophical movement that¨The Structure of Scientific Revolutions is supposed to have laid to rest. So Kuhn's endorsement of this Darwinian account does little to set his views apart from more traditional ones.
This aspect of The Road Since Structure illustrates a remarkable fact about Kuhn's revolution in the philosophy of science: the philosophical tradition that it overturned was one of which Kuhn himself was almost completely ignorant. It is not just a matter of Kuhn overlooking subtleties in the views of his predecessors, and presenting what amounts to (at best) a rather coarse caricature of logical empiricism as the "received" philosophy of science. (This book contains several of Kuhn's somewhat embarrassed admissions that, before 1962, he had read almost none of the writings of the logical empiricists, relying instead on the "everyday image" of their ideas¨and it contains little evidence that he read them very seriously after that.) What is more interesting and important is that some of the central theses that Kuhn claimed to set against the tradition were actually central doctrines of logical empiricism, including the very idea of a paradigm shift: that a scientific revolution is a radical discontinuity, a transformation in the meanings of fundamental concepts through a novel "linguistic framework," was the basic lesson that the logical empiricists claimed to learn from Einstein. That Kuhn took to calling paradigms "lexical structures" further emphasizes his kinship with the tradition he supposedly overthrew.
This is all fairly familiar by now, having been the subject of many scholarly papers during the 1990s. But The Road Since Structure makes its significance especially clear. One could, after all, dismiss Kuhn's misrepresentations of his predecessors by appealing to a standard Kuhnian claim: misrepresenting the past is absolutely typical of scientific (and other) revolutions, and even necessary and fruitful, insofar as it enables a new disciplinary framework to define its own problems and methods all the more sharply. If the philosophy of science has become more and better engaged with the history of science, and generally more alive to the complexity of scientific practice, does it really matter whether Kuhn had any clear sense of the "received view" and where he stood in relation to it?
It matters because, as this collection shows, some of the most important philosophical preoccupations of Kuhn's later work¨and of his ultimately "unfinished business"¨were precisely those of logical empiricism: How do theoretical frameworks, or "lexical structures", determine the meanings of fundamental concepts? How do such structures connect with "reality", or, more to the point, with the observations and experiments of individual scientists, and how do such connections undergo revolutionary change? On the first question, Kuhn frequently cited force and mass in Newtonian physics, as concepts whose meaning can't be expressed independently of Newton's laws of motion; he puzzled over how to characterize these seeming laws of nature that are, at the same time, definitions of fundamental concepts. "For this situation, the term 'necessary' is perhaps inappropriate, but I have no better. 'Analytic' clearly will not do" (p212). But this peculiar feature of the fundamental principles of physics, that they "implicitly define" the concepts that occur in them, was something that the logical empiricists had learned from 19th-century mathematicians, and that was absolutely central to their picture of science.
On the second question, Kuhn insisted that "alterations in the way scientific terms attach to nature are not¨logical empiricism to the contrary¨purely formal or linguistic" (p204). But this was certainly not contrary to logical empiricism. Precisely because they thought of theories as "formal or linguistic" in nature, the logical empiricists held that what "attaches them to nature" must be of a completely different nature, in effect a conventional stipulation that "coordinates" theoretical elements with observable events. And so they certainly believed that changes in such connections between theory and observation, as Kuhn put it, "come about in response to pressures generated by observation or experiment, and...result in more effective ways of dealing with some aspect of natural phenomena." But, for the same reason, they never saw in this situation a problem of "incommensurability"; they thought that scientists are perfectly capable of comparing two conceptual systems and the rules that connect them with experience, and of determining which is epistemologically more satisfactory¨and that this kind of analysis is part of what distinguishes science from other human intellectual endeavours. (And, it must be said, they stood on the authority of Einstein himself, who claimed to have discovered special and general relativity by just such a conceptual analysis.) This was not a satisfactory answer to the question, and its inadequacies undoubtedly helped to prepare the way for Kuhn. But it has at least a degree of clarity that Kuhn, groping for an alternative to a "received view" that didn't really exist, never quite achieved.
It is not surprising, in the end, that "the road since Structure" should have led Kuhn back to the central philosophical problems of the tradition that he thought he was displacing. To say so is not to defend the logical empiricists, or to accuse Kuhn. It is only to recognize that, as Kuhn's last works clearly show, those problems remain¨as they have been at least since Newton¨among the most fundamental questions in the philosophy of science, and they don't go away simply because logical empiricism is pronounced dead. A better acquaintance with the blind alleys, red herrings, and insights of his predecessors might have helped Kuhn's final attack on those problems to go much further than it actually did. And it will help any reader of The Road Since Structure who wants not only to understand Kuhn's thought, but to pursue his philosophical concerns to a more successful conclusion. For either purpose this book is indispensable.˛
Robert DiSalle teaches in the Department of Philosophy at the University of Western Ontario.