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1 pdf version of the entry Scientific Revolutions from the Winter 2017 Edition of the Stanford Encyclopedia of Philosophy Edward N. Zalta Uri Nodelman Colin Allen R. Lanier Anderson Principal Editor Senior Editor Associate Editor Faculty Sponsor Editorial Board Library of Congress Catalog Data ISSN: Notice: This PDF version was distributed by request to members of the Friends of the SEP Society and by courtesy to SEP content contributors. It is solely for their fair use. Unauthorized distribution is prohibited. To learn how to join the Friends of the SEP Society and obtain authorized PDF versions of SEP entries, please visit Stanford Encyclopedia of Philosophy Copyright c 2017 by the publisher The Metaphysics Research Lab Center for the Study of Language and Information Stanford University, Stanford, CA Scientific Revolutions Copyright c 2017 by the author All rights reserved. Copyright policy: Scientific Revolutions First published Thu Mar 5, 2009; substantive revision Tue Nov 28, 2017 The topic of scientific revolutions has been philosophically important since Thomas Kuhn s account in The Structure of Scientific Revolutions (1962, 1970). Kuhn s death in 1996 and the fiftieth anniversary of Structure in 2012 have renewed attention to the issues raised by his work. It is controversial whether or not there have been any revolutions in the strictly Kuhnian sense. It is also controversial what exactly a Kuhnian revolution is, or would be. Although talk of revolution is often exaggerated, most analysts agree that there have been transformative scientific developments of various kinds, whether Kuhnian or not. However, there is considerable disagreement about their import. The existence and nature of scientific revolutions is a topic that raises a host of fundamental questions about the sciences and how to interpret them, a topic that intersects most of the major issues that have concerned philosophers of science and their colleagues in neighboring science and technology studies disciplines. Even if the so-called Scientific Revolution from Copernicus to Newton fits the attractive, Enlightenment picture of the transition from feudalism to modernity (a claim that is also contested), the putative revolutions in mature sciences (e.g., relativity and quantum mechanics) challenge this Enlightenment vision of permanent rational and methodological standards underlying objective sciences and technologies that lead society along the path of progress toward the truth about the world. Today s scientific realists are the most visible heirs of this picture. Although many philosophers and philosophically or historically reflective scientists had commented on the dramatic developments in twentiethcentury physics, it was not until Kuhn that such developments seemed so epistemologically and ontologically damaging as to seriously challenge traditional conceptions of science and hence our understanding of 1

2 knowledge acquisition generally. Why it was Kuhn s work and its timing that made the major difference are themselves interesting questions for investigation, given that others (e.g., Wittgenstein, Fleck, Bachelard, Polanyi, Toulmin, and Hanson) had already broached important Kuhnian themes. Was there a Scientific Revolution that replaced pre-scientific thinking about nature and society and thus marked the transition to modernity? Which later developments, if any, are truly revolutionary? Are attributions of revolution usually a sign of insufficient historiographical understanding? In any case, how are such episodes to be explained historically and epistemologically? Are they contingent, that is, historical accidents and thus perhaps avoidable; or are they somehow necessary to a progressive science? And, if so, why? Is there an overall pattern of scientific development? If so, is it basically one of creative displacement, as Kuhn claimed? Do all revolutions have the same structure and function, or are there diverse forms of rupture, discontinuity, or rapid change in science? Do they represent great leaps forward or, on the contrary, does their existence undercut the claim that science progresses? Does the existence of revolutions in mature sciences support a postmodern or postcritical (Polanyi) rather than a modern, neo-enlightenment conception of science in relation to other human enterprises? Does their existence support a strongly constructionist versus a realist conception of scientific knowledge claims? Are revolutions an exercise in rationality or are they so excessive as to be labeled irrational? Do they invite epistemological relativism? What are the implications of revolution for science policy? This entry will survey some but not all of these issues. 1. The Problems of Revolution and Innovative Change 2. History of the Concept of Scientific Revolution 2.1 Scientific Revolution as a Topic for Historiography of Science 2.2 Scientific Revolution as a Topic for Philosophy 2.3 Criteria for Identifying Scientific Revolutions 3. Kuhn s Early Account of Scientific Revolutions 3.1 Kuhn s Early Model of Mature Scientific Development 3.2 Revolution as Incommensurable Paradigm Change 3.3 Progress through Revolutions 3.4 Revolution or Evolution? 4. Kuhn s Later Account of Scientific Revolutions 5. Larger Formations and Historical A Prioris: The Germanic and French Traditions 5.1 Thomas Kuhn: Kantian or Hegelian? 5.2 The German Neo-Kantian Tradition 5.3 The French Discontinuity Theorists 5.4 Kuhn s Relation to the Germanic and French Traditions 6. Other Revolution Claims and Examples 6.1 Some Alternative Conceptions of Scientific Revolution 6.2 Some Biological Cases 6.3 Nonlinear Dynamics 6.4 The Essential Tension between Tradition and Innovation Bibliography Academic Tools Other Internet Resources Related Entries 1. The Problems of Revolution and Innovative Change The difficulties in identifying and conceptualizing scientific revolutions involve many of the most challenging issues in epistemology, methodology, ontology, philosophy of language, and even value theory. 2 Stanford Encyclopedia of Philosophy Winter 2017 Edition 3

3 With revolution we immediately confront the problem of deep, possibly noncumulative, conceptual and practical change, now in modern science itself, a locus that Enlightenment thinkers would have found surprising. And since revolution is typically driven by new results, or by a conceptual-cum-social reorganization of old ones, often highly unexpected, we also confront the hard problem of understanding creative innovation. Third, major revolutions supposedly change the normative landscape of research by altering the goals and methodological standards of the enterprise, so we face also the difficult problem of relating descriptive claims to normative claims and practices, and changes in the former to changes in the latter. Comparing the world of business innovation and economic theory provides a perspective on the difficulty of these problems, for both the sciences and the industrial technologies change rapidly and sometimes deeply (in the aforementioned ways), thanks to what might be termed innovation push both the pressure to innovate (to find and solve new problems, thereby creating new designs) and the pressure to accommodate innovation (see, e.g., Christensen 1997; Christensen and Raynor, 2003; Arthur 2009). In a market economy, as in science, there is a premium on change driven by innovation. Yet most economists have treated innovations as exogenous factors as accidental, economically contingent events that come in from outside the economic system to work their effects. It is surprising that only recently has innovation become a central topic of economic theorists. Decades ago, the Austrian-American economist Joseph Schumpeter characterized economic innovation as the process of industrial mutation if I may use that biological term that incessantly revolutionizes the economic structure from within, incessantly destroying the old one, incessantly creating a new one. This process of Creative Destruction is the essential fact about capitalism. [1942, chap. VII; Schumpeter s emphasis] Unfortunately, economists largely ignored this sort of claim (made also by a few others) until the recent development of economic growth theory (e.g., Robert Solow, Paul Romer, and W. Brian Arthur: see Beinhocker 2006 and Warsh 2006). The result was an inability of economic models to account for economic innovation endogenously and, thereby, to gain an adequate understanding of the generation of economic wealth. The parallel observation holds for philosophy of science. Here, too, the leading philosophers of science until the 1960s the logical empiricists and the Popperians rejected innovation as a legitimate topic, even though it is the primary intellectual driver of scientific change and producer of the wealth of skilled knowledge that results. The general idea is that the socalled context of discovery, the context of creatively constructing new theories, experimental designs, etc., is only of historical and psychological interest, not epistemological interest, and that the latter resides in the epistemic status of the final products of investigation. On this view, convincing confirmation or refutation of a claim enables scientists to render an epistemic judgment that detaches it from its historical context. This judgment is based on the logical relations of theories and evidence rather than on history or psychology. According to this traditional view, there exists a logic of justification but not a logic of discovery. The distinction has nineteenth-century antecedents (Laudan 1980). Cohen and Nagel (1934) contended that to take historical path into account as part of the epistemic assessment was to confuse historical questions with logical questions and thereby to commit what they called a genetic fallacy. However, the context of discovery / context of justification distinction (or family of distinctions) is often attributed to Reichenbach (1938). (See the entry on Reichenbach. For recent discussion see Schickore and Steinle, 2006.) Today there are entire academic industries devoted to various aspects of the topic of scientific revolutions, whether political or scientific, yet we 4 Stanford Encyclopedia of Philosophy Winter 2017 Edition 5

4 have no adequate general theory or model of revolutions in either sphere. This article will focus on Thomas Kuhn s conception of scientific revolutions, which relies partly on analogies to political revolution and to religious conversion. Kuhn s is by far the most discussed account of scientific revolutions and did much to reshape the field of philosophy of science, given his controversial claims about incommensurability, rationality, objectivity, progress, and realism. For a general account of Kuhn s work, see the entry on Kuhn. See also Hoyningen-Huene (1993), and Bird (2001). 2. History of the Concept of Scientific Revolution What history lies behind the terms revolution and scientific revolution? The answer is an intriguing mix of accounts of physical phenomena, political fortunes, and conceptions of chance, fate, and history. Originally a term applying to rotating wheels and including the revolution of the celestial bodies (as in Copernicus title: De Revolutionibus Orbium Coelestium) and, more metaphorically, the wheel of fortune, revolution was eventually transferred to the political realm. The term later returned to science at the metalevel, to describe developments within science itself (e.g., the Copernican Revolution ). Christopher Hill, historian of seventeenth-century Britain and of the so-called English Revolution in particular, writes: Conventional wisdom has it that the word revolution acquired its modern political meaning only after Previously it had been an astronomical and astrological term limited to the revolution of the heavens, or to any complete circular motion. [Hill 1990, 82] Hill himself dates the shift to the governmental realm somewhat earlier, pointing out that the notion of overturning was also present in groups of reformers who aspired to return human society to an earlier, ideal state: overturning as returning. This conception of revolution as overturning was compatible with a cyclical view of history as a continuous process. It was in the socio-political sphere that talk of revolution as a successful uprising and overturning became common. In this sense, a revolution is a successful revolt, revolution being an achievement or product term, whereas to revolt is a process verb. The fully modern conception of revolution as involving a break from the past an abrupt, humanly-made overturning rather than a natural overturning depended on the linear, progressive conception of history that perhaps originated in the Italian Renaissance, gained strength during the Protestant Reformation and the two later English revolutions, and became practically dogma among the champions of the scientific Enlightenment. The violent English Revolution of the 1640s gave political revolution a bad name, whereas the Glorious Revolution of 1688, a bloodless, negotiated compromise, reversed this reputation. 2.1 Scientific Revolution as a Topic for Historiography of Science When did the term revolution become a descriptor of specifically scientific developments? In the most thorough treatment of the history of the concept of scientific revolution, I. B. Cohen (1985) notes that the French word revolution was being used in early eighteenth-century France to mark significant developments. By mid-century it was pretty clear that Clairaut, D Alembert, Diderot and others sometimes applied the term to scientific developments, including Newton s achievement but also to Descartes rejection of Aristotelian philosophy. Cohen fails to note that Émilie Du Châtelet preceded them, in her Institutions de Physique of 1740, where she distinguished scientific from political revolutions (Châtelet and Zinnser 2009, p. 118). However, the definition of revolution in the Encyclopédie of the French philosophes was still political. Toward 6 Stanford Encyclopedia of Philosophy Winter 2017 Edition 7

5 the end of the century, Condorcet could speak of Lavoisier as having brought about a revolution in chemistry; and, indeed, Lavoisier and his associates also applied the term to their work, as did Cuvier to his. Meanwhile, of course, Kant, in The Critique of Pure Reason (first edition 1781), spoke of his Copernican Revolution in philosophy. In fact, Cohen (1985) and Ian Hacking (2012) credit Kant with originating the idea of a scientific revolution, although Kant had read Du Châtelet. Interestingly, for Kant (1798) political revolutions are, by nature, unlawful, whereas Locke, in his social contract theory, had permitted them under special circumstances. It was during the twentieth century that talk of scientific revolutions slowly gained currency. One can find scientists using the term occasionally. For example, young Einstein, in a letter to his friend Habicht, describes his new paper on light quanta as very revolutionary (Klein 1963, 59). The idea of radical breaks was foreign to such historians of science as Pierre Duhem and George Sarton, but Alexandre Koyré, in Études Galiléennes (1939), rejected inductivist history, interpreting the work of Galileo as a sort of Platonic intellectual transformation. (See Zambelli (2016) for a revealing account of Koyré s own background.) In The Origins of Modern Science: (1949 and later editions), widely used as a course text, Herbert Butterfield, a political historian working mainly from secondary sources, wrote a compact summary of the Scientific Revolution, one that emphasized the importance of conceptual transformation rather than the infusion of new empirical information. The anti-whiggism that he had advocated in his The Whig Interpretation of History (1931) became a major constraint on the new historiography of science, especially in the Anglophone world. In Origins, Butterfield applied the revolution label not only to the Scientific Revolution and to several of its components but also to The Postponed Revolution in Chemistry (a chapter title), as if it were a delayed component of the Scientific Revolution. His history ended there. A revolution for Butterfield is a major event that founds a scientific field. Taken together, these revolutions founded modern science. As the title of his book suggests, he was concerned with origins, not with what comes after the founding. In the Introduction he famously (or notoriously) stated that the Scientific Revolution outshines everything since the rise of Christianity and reduces the Renaissance and Reformation to the rank of mere episodes, mere internal displacements, within the system of medieval Christendom. For Butterfield, the Scientific Revolution was a watershed event on the scale of total human history, an event that, somewhat ironically and somewhat like Christianity according to its believers, enabled the sciences, to some degree, to escape from history and thereby to become exceptional among human endeavors. Subsequently, A. Rupert Hall, a full-fledged historian of science who worked from primary sources, published The Scientific Revolution: (Hall 1954). Soon many other scholars spoke of the Scientific Revolution, the achievements of the period from Copernicus to Newton, including such luminaries as Kepler, Galileo, Bacon, Descartes, Huygens, Boyle, and Leibniz. Then Thomas Kuhn and Paul Feyerabend challenged received views of science and made talk of revolutionary breaks and incommensurability central to the emerging new field of history and philosophy of science. They asserted that major conceptual changes lay in the future of mature, modern sciences as well as in their past. Kuhn (1962, ch. IX) contended that there will be no end to scientific revolutions as long as systematic scientific investigation continues, for they are a necessary vehicle of ongoing scientific progress necessary to break out of dated conceptual frameworks. In other words, there are both founding revolutions, in something like Butterfield s sense of threshold events to maturity, and a 8 Stanford Encyclopedia of Philosophy Winter 2017 Edition 9

6 never-ending series of later revolutions within an ongoing field, no matter how mature it is. However, soon after Structure, Kuhn had second thoughts and eventually abandoned the Butterfield conception of revolution, on the ground that even his so-called preparadigm schools had their paradigms (Kuhn 1974, 460, note 4; details below). So multiple Kuhnian paradigms in long-term competition now became possible. The Scientific Revolution was the topic around which the field of history of science itself came to maturity. Kuhn s popularization of the idea that even the mature natural sciences undergo deep conceptual change stimulated much general intellectual interest in the history of science during the 1960s and 1970s. The revolution frame of reference was also a boon to historiographical narrative itself (see Cohen 1985 and Nickles 2006). And by challenging the received, quasi-foundational, Enlightenment conception of science, history of science and related philosophies of science gained great cultural significance for a time. In recent decades, however, many historians have contested even the claim that there was a single, coherent development appropriately called the Scientific Revolution. Steven Shapin (1996, 1) captured the unease in his opening sentence: There was no such thing as the Scientific Revolution, and this is a book about it. Everyone agrees that a series of rapid developments of various kinds took place during the period in question, but the operative word here is various. One difficulty is that no one has succeeded in capturing a 150-year (or more) period of work in an insightful, widely accepted characterization that embraces the important changes in theory, method, practices, instrumentation, social organization, and social status ranging over such a wide variety of projects. The very attempt has come to seem reductionist. Older styles of historical writing were characterized by grand narratives such as the mechanization of the world picture (Dijksterhuis 1961; original, Dutch edition, 1950) and humanity s passage from subjective superstition to objectivity and mathematical precision (Gillispie 1960). Philosophically oriented writers attempted to find unity and progress in terms of the discovery of a new, special scientific method. Today even most philosophers of science dismiss the claim that there exists a powerful, general, scientific method, the discovery of which explains the Scientific Revolution and the success of modern science. Quite the contrary: effective scientific methods are themselves the product of painstaking work at the frontier scientific results methodized and are hence typically laden with the technical content of the specialty in question. There is no content-neutral, thereby general and timeless method that magically explains how those results were achieved (Schuster and Yeo 1986, Nickles 2009). Continuity theorists such as Pierre Duhem (1914), John Herman Randall (1940), A. C. Crombie (1959, 1994), and more recent historians such as Peter Dear (2001) have pointed out a second major difficulty in speaking of the Scientific Revolution. It is hard to locate the sharp break from medieval and Renaissance practices that discontinuity historians from Koyré to Kuhn have celebrated. When examined closely in their own cultural context, all the supposed revolutionaries are found to have had one foot in the old traditions and to have relied heavily on the work of predecessors. In this vein, J. M. Keynes famously remarked that Newton was the last of the magicians, not the first of the age of reason (Keynes 1947). Still, most historians and philosophers would agree that the rate of change of scientific development increased notably during this period. Hence, Shapin, despite his professional reservations, could still write an instructive, synthetic book about the Scientific Revolution. The most thorough appraisal of historiographical treatments of the Scientific Revolution is H. Floris Cohen s (1994). The Scientific Revolution supposedly encompassed all of science or natural philosophy, as it then existed, with major social implications, as opposed to more recent talk of revolutions within particular technical 10 Stanford Encyclopedia of Philosophy Winter 2017 Edition 11

7 fields. Have there been other multidisciplinary revolutions? Some have claimed the existence of a second scientific revolution in the institutional structure of the sciences in the decades around 1800, especially in France, others (including Kuhn 1977a, ch. 3) of a multidisciplinary revolution in the Baconian sciences (chemistry, electricity, magnetism, heat, etc.) during roughly the same time period. Enrico Bellone 1980), Kuhn, and others Kuhn have focused on the tremendous increase in mathematical abstraction and sophistication during the early-to-mid nineteenth century that essentially created what we know as mathematical physics. Still others have claimed that there was a general revolution in the sciences in the decades around (See also Cohen 1985, chap. 6, for discussion of these claims.) For many historians, the Scientific Revolution now describes a topic area rather than a clearly demarcated event. They find it safer to divide the Scientific Revolution into several more topic- and project-specific developments. However, in their unusually comprehensive history of science textbook, Peter Bowler and Iwan Morus (2005) query of practically every major development they discuss whether or not it was a genuine revolution at all, at least by Kuhnian standards. More recently, David Wootton s (2015) is a revisionist account that returns to a more heroic understanding of the Scientific Revolution. 2.2 Scientific Revolution as a Topic for Philosophy Commitment to the existence of deep scientific change does not, for all experts, equate to a commitment to the existence of revolutions in Kuhn s sense. Consider the historically oriented philosopher Stephen Toulmin (1953, 1961, 1972), who wrote of ideals of natural order, principles so basic that they are normally taken for granted during an epoch but that are subject to eventual historical change. Such was the change from the Aristotelian to the Newtonian conception of inertia. Yet Toulmin remained critical of revolution talk. Although the three influential college course texts that he co-authored with June Goodfield recounted the major changes that resulted in the development of several modern sciences (Toulmin and Goodfield 1961, 1962, 1965), these authors could write, already about the so-called Copernican Revolution: We must now look past the half-truths of this caricature, to what Copernicus attempted and what he in fact achieved. For in science, as in politics, the term revolution with its implication that a whole elaborate structure is torn down and reconstructed overnight can be extremely misleading. In the development of science, as we shall see, thorough-going revolutions are just about out of the question. [1961, 164] The Toulmin and Goodfield quotation invites us to ask, When did talk of scientific revolutions enter philosophy of science in a significant way? And the answer seems to be: there is a sprinkling of uses of the term scientific revolution and its cognates prior to Kuhn, but these were ordinary expressions that did not yet have the status of a technical term. Given the prominence of the topic today, it is surprising that we do not find the term in Philipp Frank s account of the positivist discussion group in Vienna in the early twentieth century. However, Frank (1957) does speak of their perception of a crisis in modern physics caused by the undermining of classical mechanics by special relativity and quantum mechanics, and it was common to speak of this or that worldview or world picture (Weltanschauung, Weltbild), e.g., the electromagnetic vs. the Einsteinian vs. the mechanical picture. Nor do we find talk of scientific revolutions in the later Vienna Circle, even after the diaspora following the rise of Hitler. The technical term does not appear in Karl Popper s Logik der Forschung (1934) nor in his 1959 English expansion of that work as The Logic of Scientific Discovery, at least not important enough to be 12 Stanford Encyclopedia of Philosophy Winter 2017 Edition 13

8 indexed. Hans Reichenbach (1951) speaks rather casually of the revolutions in physics. The technical term is not in Ernest Nagel s The Structure of Science (1961). Nor is it in Stephen Pepper s World Hypotheses (1942). It plays no significant role in N. R. Hanson s Patterns in Discovery (1958), despite its talk of the theory-ladenness of observation and perceptual Gestalt switches. Meanwhile, there were, of course, a few widely-read works in the background that spoke of major ontological changes associated with the rise of modern science, especially E. A. Burtt s Metaphysical Foundations of Modern Physical Science (1924). Burtt s book influenced Koyré, who, in turn, influenced Kuhn. In his retrospective autobiographical lecture at Cambridge in 1953, Popper did refer to the dramatic political and intellectual events of his youth as revolutionary: [T]he air was full of revolutionary slogans and ideas, and new and often wild theories. Among the theories which interested me Einstein s theory of relativity was no doubt by far the most important. The others were Marx s theory of history, Freud s psycho-analysis, and Alfred Adler s so-called individual psychology. [Popper 1957] And during the 1960s and 1970s, Popper indicated that, according to his critical approach to science and philosophy, all science should be revolutionary revolution in permanence. But this was a tame conception of revolution compared to Kuhn s, given Popper s two logical criteria for a progressive new theory: (a) it must logically conflict with its predecessor and overthrow it; yet (b) a new theory, however revolutionary, must always be able to explain fully the success of its predecessor (Popper 1975). As we shall see, Kuhn s model of revolution rejects both these constraints (depending on how one interprets his incommensurability claim) as well as the idea of progress toward final, big, theoretical truths about the universe. Kuhn dismissed Popper s notion of revolution in perpetuity as a contradiction in terms, on the ground that a revolution is something that overthrows a long and well established order, in violation of the rules of that order. Kuhn (1970) also vehemently rejected Popper s doctrine of falsification, which implied that a theory could be rejected in isolation, without anything to replace it. According to Popper, at any time there may be several competing theories being proposed and subsequently refuted by failed empirical tests rather like several balloons being launched, over time, and then being shot down, one by one. Popper s view thus faces the difficulty, among others, of explaining the long-term coherence that historians find in scientific research. Beginning in the 1960s, several philosophers and historians addressed this difficulty by proposing the existence of larger units (than theories) of and for analysis. Kuhn s paradigms, Imre Lakatos s research programmes, Larry Laudan s research traditions (Lakatos 1970, Laudan 1977), and the widespread use of terms such as conceptual scheme, conceptual framework, worldview, and Weltanschauung (Suppe 1974) instanced this felt need for larger-sized units among Anglo-American writers, as had Toulmin s old concept of ideals of natural order. These stable formations correspondingly raised the eventual prospect of larger-scale instabilities, for an abrupt change in such a formation would surely be more dramatic, more revolutionary, than a Popperian theory change. However, none of the other writers endorsed Kuhn s radical conception of scientific revolution. Meanwhile, Michel Foucault 1963, 1966, 1969, 1975), working in a French tradition, was positing the existence of discursive formations or epistemes, sets of deep-structural cultural rules that define the limits of discourse during a period. Section 5 returns to this theme. 2.3 Criteria for Identifying Scientific Revolutions 14 Stanford Encyclopedia of Philosophy Winter 2017 Edition 15

9 I. B. Cohen (1985, chap. 2) lays down four historical tests, four necessary conditions, for the correct attribution of a revolution. First, the scientists involved in the development must perceive themselves as revolutionaries, and relevant contemporaries must agree that a revolution is underway. Second, documentary histories must count it as a revolution. Third, later historians and philosophers must agree with this attribution and, fourth, so must later scientists working in that field or its successors. By including both reports from the time of the alleged revolution and later historiographical judgments, Cohen excludes people who claimed in their day to be revolutionaries but who had insufficient impact on the field to sustain the judgment of history. He also guards against whiggish, post hoc attributions of revolution to people who had no idea that they were revolutionaries. His own four examples of big scientific revolutions all have an institutional dimension: The Scientific Revolution featured the rise of scientific societies and journals, the second was the aforementioned revolution in measurement from roughly 1800 to 1850 (which Kuhn, too, called the second scientific revolution ; 1977, 220). Third is the rise of university graduate research toward the end of that century. Fourth is the post-world War II explosion in government funding of science and its institutions. Cohen sets the bar high. Given Copernicus own conservatism and the fact that few people paid attention to his work for half a century, the Copernican achievement was not a revolution by Cohen s lights. Or if there was a revolution, should it not be attributed to Kepler, Galileo, and Descartes? This thought further problematizes the notion of revolution, for science studies experts as well as scientists themselves know that scientific and technological innovation can be extremely nonlinear in the sense that a seemingly small, rather ordinary development may eventually open up an entire new domain of research problems or a powerful new approach. Consider Planck s semi-classical derivation of the empirical blackbody radiation law in 1900, which, under successively deeper theoretical derivations by himself and (mainly) others over the next two and a half decades, became a pillar of the revolutionary quantum theory. As Kuhn (1978) shows, despite the flood of later attributions to Planck, it is surprisingly difficult, on historical and philosophical grounds, to justify the claim that he either was, or saw himself as, a revolutionary in 1900 and for many years thereafter. (Kuhn 2000b offers a short summary.) Augustine Brannigan (1981) and Robert Olby (1985) defend similar claims about Mendel s alleged discovery of Mendelian inheritance. These examples suggest that Cohen s account of scientific revolution (and Kuhn s) is tied too closely to the idea of political revolution in placing so much weight on the intentions of the generators. In the last analysis, many would agree, revolution, like speciation in biology, is a retrospective judgment, a judgment of eventual consequences, not something that is always directly observable as such in its initial phases, e.g., in the stated the intentions of its authors. On the other hand, a counterintuitive implication of this consequentialist view of revolutions is that there can be revolution without revolt (assuming that revolt is a deliberate course of action), revolutionary work without authors, so to speak, or at least revolutionary in eventual meaning despite the authors intentions. Then why not just speak of evolution rather than revolution in such cases? For, as we know by analogy from evolutionary biology, in the long run evolution can be equally transformative, even moreso (see below). A related point is that, insofar as revolutions are highly nonlinear, it is difficult to ascribe to them any particular reason or cause; for, as indicated, the triggering events can be quite ordinary work, work that unexpectedly opens up new vistas for exploration. A small cause may have an enormous effect. To be sure, the state of the relevant scientific system must be such that the events do function as triggers, but we need not expect that such a system always be readily identifiable as one in crisis in Kuhn s sense. Rather, the highly nonlinear revolutionary developments can be regarded 16 Stanford Encyclopedia of Philosophy Winter 2017 Edition 17

10 as statistical fluctuations out of a noisy background of ordinary work. At any rate, on this view it is a mistake to think that explaining revolutions requires locating a momentous breakthrough (Nickles 2012a and b). What of the common requirement that revolutions be rapid, event-like, unlike the century-and-a half-long Scientific Revolution? Brad Wray (2011, 42f) answers that there is no reason that a revolution need be an abrupt event. What is important is how thoroughgoing the change is and that it be change at the community level rather than a Gestalt switch experienced by certain individuals. (After the original publication of Structure, Kuhn acknowledged his confusion in attributing Gestalt switches to the community as a whole as well as to individuals.) On Wray s view, evolution and revolution are not necessarily opposed categories. And with this understanding, the Toulmin and Goodfield comment quoted above becomes compatible with revolutionary transformation, which, not surprisingly, takes time to become thoroughgoing. Meanwhile, the Butterfield quotation suggests that what counts as a striking change is a matter of historical scale. By our lights today, 150 years is a long time; but, against the long sweep of total human history, a change of the magnitude of the Scientific Revolution was quite rapid. Perhaps today s rapid pace of scientific and technological innovation makes us impatient with slower-scaled developments in the past. And it is surely the case the some of the slow, large-scale transformations now underway are scarcely visible to us. Finally, what of Butterfield s criterion of broader social impacts? Kuhn retained this criterion in The Copernican Revolution, but revolutions increasingly become changes in specialist communities in his later work, since those communities insulate themselves from the larger society. In the chapter on the invisibility of revolutions in Structure, Kuhn tells us that a tiny subspecialty can undergo a revolution that looks like a cumulative change even to neighboring fields of the same scientific discipline. In this respect Kuhn remained an internalist. 3. Kuhn s Early Account of Scientific Revolutions Although virtually no one in the science studies fields accepts Kuhn s model in Structure as correct in detail, there has been a revival of interest in his views since his death and, more recently, in connection with the fiftieth anniversary in 2012 of the book s original publication. Some examples are: the fiftieth anniversary edition of Structure itself, including a valuable introduction by Ian Hacking; Kuhn (2000a), a collection that records the later evolution of Kuhn s thought; Sankey (1997); Bitbol (1997); Fuller (2000); Bird (2001); Friedman (2001); Andersen (2001); Sharrock and Read (2002); Nickles (2003a); González (2004); Soler et al. (2008); Agazzi (2008); Gattei (2008); Torres (2010); Wray (2011), Kindi and Arabatzis (2012), De Langhe (2013), Marcum (2015), and Richards and Daston (2016). Kuhn on revolutions has helped to shape many symposia on scientific realism and related matters, for example, Soler (2008) on contingency in the historical development of science and Rowbottom and Bueno (2011) on Bas van Fraassen s (2002) treatment of stance, voluntarism, and the viability of empiricism. Since Kuhn s work is discussed in some detail in other contributions to this Encyclopedia (see, especially, Kuhn, Thomas, and The Incommensurability of Scientific Theories ), a brief account will suffice here. For a detailed reading guide to Structure, consult Preston (2008). 3.1 Kuhn s Early Model of Scientific Development According to Kuhn in Structure, a loosely characterized group of activities, often consisting of competing schools, becomes a mature science when a few concrete problem solutions provide models for what good research is (or can be) in that domain. These exemplary problems- 18 Stanford Encyclopedia of Philosophy Winter 2017 Edition 19

11 cum-solutions become the basis of a paradigm that defines what it is to do normal science. As its name suggests, normal science is the default state of a mature science and of the community of researchers who constitute it. The paradigm informs investigators what their domain of the world is like and practically guarantees that all legitimate problems can be solved in its terms. Normal science is convergent rather than divergent: it actively discourages revolutionary initiatives and essentially novel (unexpected) discoveries, for these threaten the paradigm. However, normal research is so detailed and focused that it is bound to turn up anomalous experimental and theoretical results, some of which will long resist the best attempts to resolve them. Given the historical contingencies involved in the formation of guiding paradigms as well as the fallibility of all investigators, it would be incredibly improbable for everything to end up working perfectly. According to Kuhn, anomalies are therefore to be expected. Historically, all paradigms and theory complexes face anomalies at all times. If and when persistent efforts by the best researchers fail to resolve the anomalies, the community begins to lose confidence in the paradigm and a crisis period ensues in which serious alternatives can now be entertained. If one of these alternatives shows sufficient promise to attract a dominant group of leading researchers away from the old paradigm, a paradigm shift or paradigm change occurs and that is a Kuhnian revolution. The radicals accomplish this by replacing the former set of routine problems and problem-solving techniques (exemplars) by a new set of exemplars, making the old practices seem defective, or at least old fashioned. 3.2 Revolution as Incommensurable Paradigm Change The new paradigm overturns the old by displacing it as no longer a competent guide to future research. In the famous (or notorious)chapter X of Structure, Kuhn claims that the change is typically so radical that the two paradigms cannot be compared against the same goals and methodological standards and values. Moreover, the accompanying meaning shift of key terms, such as simultaneous, mass, and force in physics, leads to communication breakdown. In effect, scientists on different sides of a paradigm debate live in different worlds. Kuhn speaks of scientists experiencing a kind of gestalt switch or religious conversion experience. The heated rhetoric of debate and the resulting social reorganization, he says, resemble those of a political revolution. Like the choice between political institutions, that between competing paradigms proves to be a choice between incompatible modes of community life (1970, 94). The comparison of scientific with political revolutions should not surprise, given the entangled history of the term revolution, but claiming such close similarity enraged philosophical and cultural critics of Kuhn. The typical paradigm change does not involve a large infusion of new empirical results, Kuhn tells us (chs. IX and X). Rather, it is a conceptual reorganization of otherwise familiar materials, as in the relativity revolution. A paradigm change typically changes goals, standards, linguistic meaning, key scientific practices, the way both the technical content and the relevant specialist community are organized, and the way scientists perceive the world. (For the often neglected practices dimension in Kuhn s account, see Rouse, 2003.) Nor can we retain the old, linear, cumulative conception of scientific progress characteristic of Enlightenment thinking; for, Kuhn insists, attempts to to show that the new paradigm contains the old, either logically or in some limit or under some approximation, will be guilty of a fallacy of equivocation. The meaning change reflects the radical change in the assumed ontology of the world. A second Kuhnian objection to cumulative progress is what has come to be called Kuhn loss (see Post 1971, 229, n. 38). Rarely does the new paradigm solve all of the problems that its predecessor apparently solved. So even in this sense the new paradigm fails completely to enclose the old. The consequence, according to Kuhn, is that attempts to defend 20 Stanford Encyclopedia of Philosophy Winter 2017 Edition 21

12 continuous, cumulative scientific progress by means of theory reduction or even a correspondence relationship (e.g., a limiting relationship) between a theory and its predecessor must fail. Revolutions produce discontinuities. Given all these changes, Kuhn claimed that the two competing paradigms are incommensurable, a technical term that he repeatedly attempted to clarify. Traditional appeals to empirical results and logical argument are insufficient to resolve the debate. For details of the incommensurability debate, see the entry The Incommensurability of Scientific Theories. as well as Hoyningen-Huene and Sankey (2001) as a sample of the large literature on incommensurability. Naturally, many thinkers of a logical empiricist or Popperian bent, or simply of an Enlightenment persuasion, were shocked by these claims and responded with a barrage of criticism as if Kuhn had committed a kind of sacrilege by defiling the only human institution that could be trusted to provide the objective truth about the world. Today there is fairly wide agreement that some of Kuhn s claims no longer look so radical. Meanwhile, Kuhn himself was equally shocked by the vehemence of the attacks and (to his mind) the willful distortion of his views (see, e.g., Lakatos and Musgrave 1970). In later papers and talks, he both clarified his views and softened some of his more radical claims. Critics reacted to the radical views of Paul Feyerabend (1962, 1975) in a somewhat similar manner. (For details, see the entry Feyerabend, Paul. ) Given that cyclic theories of history have, for the most part, long given way to linear, progressive accounts, readers may be surprised at Kuhn critic, physicist Stephen Weinberg s comment that Kuhn s overall model is still, in a sense, cyclic (Weinberg 2001). In fact, Kuhn himself had already recognized this. After the founding paradigm in Kuhn s account in Structure, we have normal science under a paradigm, then crisis, then revolution, then a new paradigm a development that brings back a new period of normal science. At this abstract level of description, the model is indeed cyclic, but of course the new paradigm heads the science in question in a new direction rather than returning it to a previous state. Other commentators, including Marxists, have regarded Kuhn s mechanism as dialectical, as illustrated by the succession of selfundermining developments in the theory of light, from a Newtonian particle theory to a wave theory to a new kind of wave-particle duality. (For the dialectical interpretation see especially Krajewski 1977 and Nowak 1980 on the idealizational approach to science, as originated by Karl Marx.) Somewhat ironically, Kuhn s attempt to revolutionize the epistemology of science has had a wider socio-cultural impact than many scientific revolutions themselves. While some of Kuhn s doctrines step into the postmodern era, he still had a foot in the Enlightenment, which helps to explain his dismay at the critical reaction to his work and to radical developments in the new-wave sociology of science of the 1970s and 80s. For, unlike many postmodernists (some of whom make use of his work), Kuhn retained a scientific exceptionalism. He did not doubt that the sciences have been uniquely successful since the Scientific Revolution. For him, unlike for many of his critics, revolutions in his radical sense were great epistemological leaps forward rather than deep scientific failures. On the science policy front, he intended his work to help preserve the integrity of this socially valuable enterprise. It is on science policy issues that Steve Fuller is most critical of Kuhn (Fuller 2000). The general problem presented by Kuhn s critique of traditional philosophy of science is that, although the various sciences have been successful, we do not understand how they have accomplished this or even how to characterize this success. Enlightenment-style explanations have failed. For example, Kuhn and Feyerabend (1975), preceded by Popper, 22 Stanford Encyclopedia of Philosophy Winter 2017 Edition 23

13 were among the first philosophers to expose the bankruptcy of the claim that it was the discovery of a special scientific method that explains that success, a view that is still widely taught in secondary schools today. And that conclusion (one that cheered those postmodernists who regard scientific progress as an illusion) left Kuhn and the science studies profession with the problem of how science really does work. To explain how and why it had been so successful became an urgent problem for him again, a problem largely rejected as bogus by many science studies scholars other than philosophers. Another of Kuhn s declared tasks in Structure was to solve the problem of social order for mature science, that is, how cohesive modern science (especially normal science) is possible (Barnes 1982, 2003). Yet another was to bring scientific discovery back into philosophical discussion by endogenizing it in his model, while denying the existence of a logic of discovery. Whereas the logical empiricists and Popper had excluded discovery issues from philosophy of science in favor of theory of confirmation or corroboration, Kuhn was critical of confirmation theory and supportive of historical and philosophical work on discovery. He argued that discoveries are temporally and cognitively structured and that they are an essential component of an epistemology of science. In Kuhnian normal science the problems are so well structured and the solutions so nearly guaranteed in terms of the resources of the paradigm that the problems reduce to puzzles (Nickles 2003b). Kuhn kept things under control there by denying that normal scientists seek essential innovation, for, as indicated above, major, unexpected discoveries threaten the extant paradigm and hence threaten crisis and revolution. So, even in normal science, Kuhn had to admit that major discoveries are unexpected challenges to the reigning paradigm. They are anomalous, even exogenous in the sense that they come as shocks from outside the normal system. But this is the working scientists point of view. As noted, normal science is bound to turn up difficulties that resist resolution, at least some of which are sooner or later recognized by the community. In Kuhn s own view, as a historian and philosopher standing high above the fray, it is deliberate, systematic normal research that will most readily sow the seeds of revolution and hence of rapid scientific progress. According to the old musicians joke, the fastest way to Carnegie Hall is slow practice. For Kuhn the fastest way to revolutionary innovation is intensely detailed normal science. When it comes to revolution on Kuhn s account, the social order breaks down dramatically. And here his strategy of taming creative normal research so as to make room for articulated discovery (the reduction of research problems to puzzles) also breaks down. Kuhn had to acknowledge that he had no idea how the scientists in extraordinary research contexts manage to come up with brilliant new ideas and techniques. This failure exacerbated his problem of explaining what sort of continuity underlies the revolutionary break that enables us to identify the event as a revolution within an ongoing field of inquiry. As he later wrote: Even those who have followed me this far will want to know how a value-based enterprise of the sort I have described can develop as a science does, repeatedly producing powerful new techniques for prediction and control. To that question, unfortunately, I have no answer at all. [1977b, 332] 3.3 Progress through Revolutions Kuhn s work on scientific revolutions raises difficult questions about whether science progresses and, if so, in what that progress consists. Kuhn asks (p. 60), Why is progress a perquisite reserved almost exclusively for 24 Stanford Encyclopedia of Philosophy Winter 2017 Edition 25