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The main message of The Structure of Scientific Revolutions – Wikipedia (SSR) could be restated as science is self-correcting though individual scientists may not be or science is rational though individual scientists may not be. A facetious one is an abbreviated version of Planck’s principle – Wikipedia, (Max Planck – Wikiquote),

‘Science advances one funeral at a time’

Perspective: Kuhn, The Apple Cart Upsetter

Kuhn’s singular and unprecedented insight came by questioning the then prevailing consensus that being progressive and cumulative constitute the dominant attributes of scientific progress. Progressive and cumulative imply steady, thoughtful, rational, unemotional, and yet the history of scientific progress suggests it has been anything but. There’s an eerie resonance to Kuhn’s synthesis in the The Sleepwalkers – Wikipedia, a 1959 book by Arthur Koestler – Wikipedia,

‘The progress of science is generally regarded as a kind of clean, rational advance along a straight ascending line; in fact it has followed a zigzag course, at times more bewildering than the evolution of political thought.’

Three years later, in 1962 Kuhn wrote (1, p.208, emphasis mine),

‘scientific development as a succession of tradition-bound periods punctuated by non-cumulative breaks

Kuhn’s thesis was a poke in the eye for philosophy titans like Karl Popper (Stanford Encyclopedia of Philosophy) who’d held sway until then with their contention that science was a unique human endeavor for objective pursuit of truth, that scientific progress, i.e., the discovery of new facts, followed from scientists calmly, objectively and rationally incorporating new data and adjusting their mental constructs accordingly in the form of new theories or hypotheses.

Kuhn comes along and says none of such accepted tropes about the scientific process are accurate, that instead

  • Science consists of periods of ‘normal’ science leavened by periods of crisis, with revolutionary science breaking the impasse, overturning and replacing the old paradigm with a new one. Thus, neither necessarily progressive nor cumulative though it could also be both.
  • Scientific education helps inculcate the unquestioning attitude and habits of ‘normal’ science (2).

Though the scientific enterprise may be open-minded, the individual scientist is very often not. Whether his work is predominantly theoretical or experimental, he usually seems to know, before his research project is well under way, all but the most intimate details of the result which that project will achieve. If the result is quickly forthcoming, well and good. If not, he will struggle with his apparatus and with his equations until, if at all possible, they will yield results which conform to the sort of pattern which he has foreseen from the start…a relatively dogmatic initiation into a pre-established problem-solving tradition that the student is neither invited nor equipped to evaluate

  • Criteria and methods scientists use to justify their choice of paradigms are habitually ambiguous and imprecise as well as inconsistent and changing.
  • ‘Normal’ scientists engage in puzzle-solving, using the prevailing paradigm as a road-map to solve remaining puzzles within a given field. Periods of ‘normal’ science thus consist of unquestioning adherence to the prevailing consensus of beliefs and methods, i.e., paradigm, and therefore as well unquestioning use of such methods in routine puzzle-solving until over time, anomalies accumulate, anomalies the prevailing paradigm fails to adequately explain and which thwart these scientists in achieving their puzzle solving goals. Tension over accumulating anomalies then leads that scientific field into a period of crisis, one eventually resolved by a revolution wherein a new theory supplants the older one by being able to adequately or better explain such anomalies. Why would such anomalies accumulate in the first place? According to Kuhn, if the scientific approach operates the way it should then, regardless of scientists, scientism and inherent biases attendant to the two, it should ferret out some undeniable truism, what Popper called verisimilitude (Verisimilitude – Wikipedia). What to do about the truism then becomes the question. Fits with the prevailing paradigm? Accept wholeheartedly. Doesn’t fit? Ignore or minimize and so anomalies accrue with time. Generation gap may also apply as in younger, presumably conceptually uncommitted or less committed, practitioners assessing the same data and the lay of the land with fresh, less biased eyes.
  • Aware of and driven by anomalies within their field, revolutionary scientists pursue answers that could explain them and in the process create revolutionary science (3).

Thus, rather than the Popperian view of science as ‘revolution in permanence‘ (4), Kuhn proposed ‘Periods of stable growth punctuated by revisionary revolutions‘ (5), with both defining scientific progress as the discovery of new facts. Which is more accurate? History of science suggests Kuhn’s.

Self-Inflicted Problem: What Did Kuhn Actually Mean By Paradigm?

Problem is Kuhn’s writing in the book he’s best known for was so ambiguous, it triggered and sustained a furore of criticism led by philosophical luminaries such as Karl Popper, Paul Feyerabend (Stanford Encyclopedia of Philosophy), Imre Lakatos (Stanford Encyclopedia of Philosophy) (4, 6, 7). Unfortunately Kuhn’s ambiguity and vague use of the word paradigm also encouraged popular culture to over-use it to the point of abuse and meaninglessness. A thorny issue fought over ever since is whether Kuhn offered prescriptions or descriptions of the scientific process.

Paul Feyerabend (Stanford Encyclopedia of Philosophy) famously wrote (6, page 198) of SSR,

Whenever I read Kuhn, I am troubled by the following question: are we here presented with methodological prescriptions which tell the scientist how to proceed; or are we given a description, void of any evaluative element, of those activities which are generally called “scientific”? Kuhn’s writings, it seems to me, do not lead to a straightforward answer. They are ambiguous in the sense that they are compatible with, and lend support to, both interpretations’

To which Thomas Kuhn (Stanford Encyclopedia of Philosophy) felt compelled to respond (6, page 237),

‘The answer, of course, is that they should be read in both ways at once. If I have a theory of how and why science works, it must necessarily have implications for the way in which scientists should behave if their enterprise is to flourish…scientists should behave essentially as they do if their concern is to improve scientific knowledge’

Margaret Masterman – Wikipedia from the Cambridge Language Research Unit carefully analyzed SSR and identified 21 different senses in which Kuhn used it, grouping them into 3 categories, metaphysical, sociological and construct. The last includes the nuts and bolts of a practicing scientist’s tool-kit including among others, standard textbooks, methods, reagents, analytical tools (8).

Sustained criticism forced Kuhn to re-analyze his position and clarify what he meant by paradigm (1, page 175, emphasis mine),

‘in much of the book the term ‘paradigm’ is used in two different senses. On the one hand, it stands for the entire constellation of beliefs, values, techniques, and so on shared by the members of a given community. On the other, it denotes one sort of element in that constellation, the concrete puzzle-solutions which, employed as models or examples, can replace explicit rules as a basis for the solution of the remaining puzzles of normal science’

In further revisions, Kuhn eventually divided his use of paradigm into two categories, disciplinary matrix, all the shared commitments of a scientific group, and exemplars as in concrete problem solutions, accepted by the group as, in a quite usual sense, paradigmatic (9). ‘Disciplinary’ as in the common possession of the practitioners of a professional discipline; ‘matrix’ as in being composed of ordered elements of various sorts, each requiring further specification. Obviously disciplinary matrix and exemplar never took off into popular culture the way paradigm did.

Meaning Kuhn intended paradigm to signify a given scientific field’s tacitly agreed upon worldview or mental construct, the corresponding tool-kit and language to define and interrogate it, and the authoritative, supportive examples of how to do science to solve remaining puzzles within that field.

Kuhn’s Prescriptions & Descriptions: How Scientists Do And Ought To Behave Go Hand In Hand

As a historian, sociologist and philosopher of science, to me Thomas Kuhn’s place is akin to that of behavioral scientists.

Classical economists schooled in the manner of Friedrich Hayek – Wikipedia or Milton Friedman – Wikipedia chose to regard individuals as rational actors making rational economic decisions. Others such as Richard Thaler – Wikipedia, Amos Tversky – Wikipedia, Daniel Kahneman – Wikipedia, Dan Ariely – Wikipedia, to name some notables, instead show that economical decision making is beset by cognitive biases that each and every one of us, the supposed rational actors, unwittingly bring to the decision making process, be it about economics or anything else for that matter.

In like manner, Kuhn may be best understood as a counterpoint to philosophers such as Karl Popper and sociologists such as Robert K. Merton – Wikipedia who envisaged scientific development as smooth, cumulative, progressive. Implicit in the latter analysis is the assumption that scientists as the players involved in the system are rational actors making unbiased decisions.

Problem with this notion is at least two-fold.

For one, we now know and understand much better in a way that wasn’t as explicitly understood in the days of Popper and Merton that we each operate within a maze of cognitive biases that constantly attend our every thought and decision. Or at least we more openly acknowledge that this is so.

For another, scientific culture gets established the same way others do, viz., individuals within the group behave and are expected to hew to a set of normative values tacitly assumed to be common to that group.

Habituation of ‘normal’ scientists, those accepting of the prevailing status quo, their habits of thought and thinking processes, their habitual experimental constructs, read-outs, and analyses, their scientific method, create a further, unbridgeable divide such that status quo acceptors and challengers live in ‘different worlds’ and their concepts are also ‘incommensurable’ (Commensurability (philosophy of science) – Wikipedia. Failure to communicate is then a predictable outcome. Language is after all an imperfect tool. Practitioners may use but imply very different meanings to the same terms. Seen in one light, per Kuhn, ‘normal’ scientists behave non-rationally, trying the same approach over and over again even when the outcome doesn’t support the prevailing paradigm. Seen in another light, the ‘revolutionary’ scientists are the non-rational actors, bucking the prevailing norm. Either view threatens the Popperian view of slow, steady, rational, relentless march of scientific progress, and philosophers continue to debate these opposing views.

For Kuhn, criteria and essentials of the scientific process go together as do how scientists do and ought to behave. Contingent on their commitment to improve scientific knowledge, Kuhn’s implications for research methodology is to make no change and to keep doing what scientists have been doing. After all, science has been spectacularly successful so far.


1. The Structure of Scientific Revolutions – Wikipedia, 2nd edition, Thomas S. Kuhn.

2. Kuhn, Thomas S. The function of dogma in scientific research. Na, 1963.

3. Maurice A. Finocchiaro. Essay-Review of Lakatos’ Criticism and the Growth of Knowledge. Studies in History and Philosophy of Science 3(1972 -73): 357-72.

4. Lakatos, Imre. “Criticism and the methodology of scientific research programmes.” Proceedings of the Aristotelian society. Vol. 69. Aristotelian Society, Wiley, 1968. Publications

5. Thomas Kuhn (Stanford Encyclopedia of Philosophy)

6. Musgrave, Alan, ed. Criticism and the Growth of Knowledge: Volume 4: Proceedings of the International Colloquium in the Philosophy of Science, London, 1965. Vol. 4. Cambridge University Press, 1970.

7. Lakatos, Imre. “Falsification and the methodology of scientific research programmes.” Can Theories be Refuted?. Springer Netherlands, 1976. 205-259. http://www.csun.edu/~vcsoc00i/cl…

8. Masterman, M. “The Nature of a Paradigm, w: Lakatos, I., Musgrave A.(eds.), Criticism and the Growth of Knowledge.” (1970).

9. Kuhn, Thomas S. “Second thoughts on paradigms.” The structure of scientific theories 2 (1974): 459-482. http://eu.pravo.hr/_download/rep…