What makes a scientific paradigm warranted

Aristotle's physics, understood on its own terms, was simply different from rather than inferior to Newtonian physics. Kuhn left physics for philosophy, and he struggled for 15 years to transform his epiphany into the theory set forth in The Structure of Scientific Revolutions.

The keystone of his model was the concept of a paradigm. Paradigm, pre-Kuhn, referred merely to an example that serves an educational purpose; amo , amas , amat , for instance, is a paradigm for teaching conjugations in Latin.

Kuhn used the term to refer to a collection of procedures or ideas that instruct scientists, implicitly, what to believe and how to work. Most scientists never question the paradigm. They solve "puzzles," problems whose solutions reinforce and extend the scope of the paradigm rather than challenging it. Kuhn called this "mopping up," or "normal science. Anomalies are often ignored, but if they accumulate they may trigger a revolution also called a paradigm shift, although not originally by Kuhn , in which scientists abandon the old paradigm for a new one.

Denying the view of science as a continual building process, Kuhn held that a revolution is a destructive as well as a creative act. The proposer of a new paradigm stands on the shoulders of giants to borrow Newton's phrase and then bashes them over the head. He or she is often young or new to the field, that is, not fully indoctrinated.

Most scientists yield to a new paradigm reluctantly. They often do not understand it, and they have no objective rules by which to judge it. Different paradigms have no common standard for comparison; they are "incommensurable," to use Kuhn's term.

Proponents of different paradigms can argue forever without resolving their basic differences because they invest basic terms—motion, particle, space, time—with different meanings. The conversion of scientists is thus both a subjective and political process. It may involve sudden, intuitive understanding—like that finally achieved by Kuhn as he pondered Aristotle. Yet scientists often adopt a paradigm simply because it is backed by others with strong reputations or by a majority of the community.

Kuhn's view diverged in several important respects from the philosophy of Karl Popper, who held that theories can never be proved but only disproved, or "falsified. A new paradigm may solve puzzles better than the old one does, and it may yield more practical applications.

Just because modern physics has spawned computers, nuclear power and CD players, he suggested, does not mean it is truer, in an absolute sense, than Aristotle's physics. Similarly, Kuhn denied that science is constantly approaching the truth.

At the end of Structure he asserted that science, like life on earth, does not evolve toward anything but only away from something. Kuhn described himself to me as a "post-Darwinian Kantian. But whereas Kant and Darwin each thought that we are all born with more or less the same, innate paradigm, Kuhn argued that our paradigms keep changing as our culture changes.

But whatever is universal in human experience, whatever transcends culture and history, is also "ineffable," beyond the reach of language. Language, Kuhn said, "is not a universal tool. It's not the case that you can say anything in one language that you can say in another. But isn't mathematics a kind of universal language? I asked. Not really, Kuhn replied, since it has no meaning; it consists of syntactical rules without any semantic content.

For example, I said, the hypothesis that AIDS is caused by the human immunodeficiency virus is either right or wrong; language and metaphysics are beside the point. Kuhn shook his head. So were his own ideas true or not? But it, like any scientific construct, has to be evaluated simply for its utility—for what you can do with it.

But then Kuhn, having set forth his bleak view of the limits of science and indeed of all human discourse, proceeded to complain about the many ways in which his book had been misinterpreted and misused, especially by admirers. Kuhn for telling us about paradigms.

Now that we know about them we can get rid of them. His protests were to no avail. He had a painful memory of sitting in on a seminar and trying to explain that the concepts of truth and falsity are perfectly valid, and even necessary—within a paradigm. I'm trying to start a revolution.

Please help me,' and accompanied by a book-length manuscript. Kuhn declared that, although his book was not intended to be pro-science, he is pro-science. He was then elected into the university's elite Society of Fellows and might have continued to work on quantum physics until the end of his days had he not been commissioned to teach a course on science for humanities students as part of the General Education in Science curriculum.

This was the brainchild of Harvard's reforming president, James Conant , who believed that every educated person should know something about science. The course was centred around historical case studies and teaching it forced Kuhn to study old scientific texts in detail for the first time. Physicists, then as now, don't go in much for history. Kuhn's encounter with the scientific work of Aristotle turned out to be a life- and career-changing epiphany.

Given that formulation, I rapidly discovered that Aristotle had known almost no mechanics at all… that conclusion was standard and it might in principle have been right. But I found it bothersome because, as I was reading him, Aristotle appeared not only ignorant of mechanics, but a dreadfully bad physical scientist as well. About motion, in particular, his writings seemed to me full of egregious errors, both of logic and of observation.

What Kuhn had run up against was the central weakness of the Whig interpretation of history. By the standards of present-day physics, Aristotle looks like an idiot. And yet we know he wasn't. Kuhn's blinding insight came from the sudden realisation that if one is to understand Aristotelian science, one must know about the intellectual tradition within which Aristotle worked.

One must understand, for example, that for him the term "motion" meant change in general — not just the change in position of a physical body, which is how we think of it.

Or, to put it in more general terms, to understand scientific development one must understand the intellectual frameworks within which scientists work.

That insight is the engine that drives Kuhn's great book. Kuhn remained at Harvard until and, having failed to get tenure, moved to the University of California at Berkeley where he wrote Structure… and was promoted to a professorship in The following year, the book was published by the University of Chicago Press. Despite the pages of the first edition, Kuhn — in his characteristic, old-world scholarly style — always referred to it as a mere "sketch".

He would doubtless have preferred to have written an page doorstop. But in the event, the readability and relative brevity of the "sketch" was a key factor in its eventual success. Although the book was a slow starter, selling only copies in , by mid it had sold , copies and sales to date now stand at 1. For a cerebral work of this calibre, these are Harry Potter-scale numbers.

Kuhn's central claim is that a careful study of the history of science reveals that development in any scientific field happens via a series of phases. The first he christened "normal science" — business as usual, if you like. In this phase, a community of researchers who share a common intellectual framework — called a paradigm or a "disciplinary matrix" — engage in solving puzzles thrown up by discrepancies anomalies between what the paradigm predicts and what is revealed by observation or experiment.

Most of the time, the anomalies are resolved either by incremental changes to the paradigm or by uncovering observational or experimental error. As philosopher Ian Hacking puts it in his terrific preface to the new edition of Structure : "Normal science does not aim at novelty but at clearing up the status quo. It tends to discover what it expects to discover. The trouble is that over longer periods unresolved anomalies accumulate and eventually get to the point where some scientists begin to question the paradigm itself.

Of course, the referentialist response shows only that reference can be retained, not that it must be. Consequently it is only a partial defence of realism against semantic incommensurability. A further component of the defence of realism against incommensurability must be an epistemic one.

For referentialism shows that a term can retain reference and hence that the relevant theories may be such that the later constitutes a better approximation to the truth than the earlier.

Nonetheless it may not be possible for philosophers or others to know that there has been such progress. Methodological incommensurability in particular seems to threaten the possibility of this knowledge. However, we never are able to escape from our current perspective. A realist response to this kind of incommensurability may appeal to externalist or naturalized epistemology. So long as the method has an appropriate kind of reliability it can generate knowledge.

Contrary to the internalist view characteristic of the positivists and, it appears, shared by Kuhn the reliability of a method does not need to be one that must be evaluable independently of any particular scientific perspective.

It is not the case, for example, that the reliability of a method used in science must be justifiable by a priori means. Thus the methods developed in one era may indeed generate knowledge, including knowledge that some previous era got certain matters wrong, or right but only to a certain degree.

A naturalized epistemology may add that science itself is in the business of investigating and developing methods. As science develops we would expect its methods to change and develop also. The social sciences in particular took up Kuhn with enthusiasm. There are primarily two reasons for this. The status as genuine sciences of what we now call the social and human sciences has widely been held in doubt.

Such disciplines lack the remarkable track record of established natural sciences and seem to differ also in the methods they employ. More specifically they fail by pre-Kuhnian philosophical criteria of sciencehood. On the one hand, positivists required of a science that it should be verifiable by reference to its predictive successes. Yet psychoanalysis, sociology and even economics have difficulty in making precise predictions at all, let alone ones that provide for clear confirmation or unambiguous refutation.

For example, Popper famously complained that psychoanalysis could not be scientific because it resists falsification. Kuhn himself did not especially promote such extensions of his views, and indeed cast doubt upon them. He denied that psychoanalysis is a science and argued that there are reasons why some fields within the social sciences could not sustain extended periods of puzzle-solving normal science b.

Although, he says, the natural sciences involve interpretation just as human and social sciences do, one difference is that hermeneutic re-interpretation, the search for new and deeper intepretations, is the essence of many social scientific enterprises. This contrasts with the natural sciences where an established and unchanging interpretation e. Re-intepretation is the result of a scientific revolution and is typically resisted rather than actively sought.

Another reason why regular reinterpretation is part of the human sciences and not the natural sciences is that social and political systems are themselves changing in ways that call for new interpretations, whereas the subject matter of the natural sciences is constant in the relevant respects, permitting a puzzle-solving tradition as well as a standing source of revolution-generating anomalies. Their judgments are nonetheless tightly constrained during normal science by the example of the guiding paradigm.

During a revolution they are released from these constraints though not completely. Consequently there is a gap left for other factors to explain scientific judgments. Later Kuhn repeated the point, with the additional examples of German Romanticism, which disposed certain scientists to recognize and accept energy conservation, and British social thought which enabled acceptance of Darwinism c, Such suggestions were taken up as providing an opportunity for a new kind of study of science, showing how social and political factors external to science influence the outcome of scientific debates.

Pickering this influence is taken to be central, not marginal, and to extend to the very content of accepted theories. Kuhn , 7. Feminists and social theorists e. Furthermore, the fact that Kuhn identified values as what guide judgment opens up the possibility that scientists ought to employ different values, as has been argued by feminist and post-colonial writers e.

Longino Kuhn himself, however, showed only limited sympathy for such developments. External history of science seeks causes of scientific change in social, political, religious and other developments of science. First, the five values Kuhn ascribes to all science are in his view constitutive of science. An enterprise could have different values but it would not be science c, ; , Secondly, when a scientist is influenced by individual or other factors in applying these values or in coming to a judgment when these values are not decisive, those influencing factors will typically themselves come from within science especially in modern, professionalized science.

Personality may play a role in the acceptance of a theory, because, for example, one scientist is more risk-averse than another c, —but that is still a relationship to the scientific evidence.

Even when reputation plays a part, it is typically scientific reputation that encourages the community to back the opinion of an eminent scientist. Thirdly, in a large community such variable factors will tend to cancel out. Kuhn supposes that individual differences are normally distributed and that a judgment corresponding to the mean of the distribution will also correspond to the judgment that would, hypothetically, be demanded by the rules of scientific method, as traditionally conceived c, This corresponds to the Kantian distinction between noumena and phenomena.

The important difference between Kant and Kuhn is that Kuhn takes the general form of phenomena not to be fixed but changeable.

One the one hand work on conceptual structures can help understand what might be correct in the incommensurability thesis Nersessian , Kuhn articulates a view according to which the extension of a concept is determined by similarity to a set of exemplary cases rather than by an intension.

On the other hand, the psychology of analogical thinking and cognitive habits may also inform our understanding of the concept of a paradigm. Kuhn, however, failed to develop the paradigm concept in his later work beyond an early application of its semantic aspects to the explanation of incommensurability.

Nonetheless, other philosophers, principally Howard Margolis , have developed the idea that habits of mind formed by training with paradigms-as-exemplars are an important component in understanding the nature of scientific development.

As explained by Nickles b and Bird , this is borne out by recent work by psychologists on model-based and analogical thinking. Unquestionably he was one of the most influential philosophers and historians of science of the twentieth century. His most obvious achievement was to have been a major force in bringing about the final demise of logical positivism. Nonetheless, there is no characteristically Kuhnian school that carries on his positive work.

It is as if he himself brought about a revolution but did not supply the replacement paradigm. But as far as the history of science and science studies more generally are concerned, Kuhn repudiated at least the more radical developments made in his name.

Turning to the philosophy of science, it was clear by the end of the s that the centreground was now occupied by a new realism, one that took on board lessons from general philosophy of language and epistemology, in particular referentialist semantics and a belief in the possibility of objective knowledge and justification.

In the hands of realists the thesis is taken to undermine the theory-observation dichotomy that permitted positivists to take an anti-realist attitude to theories.

In the hands of Kuhn however, the thesis is taken, in effect, to extend anti-realism from theories to observation also. This in turn fuels the thesis of incommensurability. The explanation of scientific development in terms of paradigms was not only novel but radical too, insofar as it gives a naturalistic explanation of belief-change.

Naturalism was not in the early s the familiar part of philosophical landscape that it has subsequently become. It may yet be that a characteristically Kuhnian thesis will play a prominent part in our understanding of science.

Life and Career 2. The Development of Science 3. The Concept of a Paradigm 4. Incommensurability and World-Change 4. History of Science 6. Criticism and Influence 6. The Development of Science In The Structure of Scientific Revolutions Kuhn paints a picture of the development of science quite unlike any that had gone before.

The Concept of a Paradigm A mature science, according to Kuhn, experiences alternating phases of normal science and revolutions.

Incommensurability and World-Change The standard empiricist conception of theory evaluation regards our judgment of the epistemic quality of a theory to be a matter of applying rules of method to the theory and the evidence. Kuhn expresses or builds on the idea that participants in different disciplinary matrices will see the world differently by claiming that their worlds are different: In a sense I am unable to explicate further, the proponents of competing paradigms practice their trades in different worlds.

For example, Kuhn says: … the physical referents of these Einsteinian concepts are by no means identical with those of the Newtonian concepts that bear the same name. Crombie ed. Lakatos and A. Musgrave, London: Cambridge University Press: 1— Musgrave eds. Suppe ed. Ortony Cambridge: Cambridge University Press: — Daston, and M. Heidelberger, Cambridge: Cambridge University Press: 7— Reprinted in Kuhn 13— Fine, M.

Forbes, and L. Hiley, J. Bohman, and R. Thomas Kuhn and the Nature of Science , edited by P. Other references and secondary literature Andersen, H. Andersen, H. Barker, and X. Barnes, B. Kuhn and Social Science , London: Macmillan. Barsalou, L. Lehrer and E. Kittay, eds. Bird, A. Soler, H. Sankey, and P. Hoyningen-Huene eds. Bruner, J. Cohen, I. Devitt, M. Doppelt, G. Evans, G. Fuller, S. Gutting, G. Hacking, I. Hanson, N.

Horwich, P. Hoyningen-Huene, P. Hung, E. Kindi, V. Kripke, S. Kroon, F. Lakatos, I. Longino, H. Margolis, H. Martin, E. Reprinted in E.

Keller and H. Longino eds. Masterman, M. Mizrahi, M. Musgrave, A. Nagel, E.