The Structure of Scientific Revolutions (50th Anniversary Edition)

This review is part of a double bill. Cold Spring Harbor Laboratory Press recently published How Scientific Progress Occurs. In it, Elof Axel Carlson explores the relevance to biology of the ideas Kuhn formulated in his book The Structure of Scientific Revolutions. This is one of those classics already on my to-do list, so I have read both books back-to-back and will review them one after the other. Anyway, who is this Kuhn and why should you care? Virtually everyone will have heard the buzzwords “paradigm” and “paradigm shift” – and for that, you can thank Kuhn.

Thomas S. Kuhn (1922-1996) was an American physicist, historian and philosopher of science whose claim to fame is this book. Initially published as a 1962 essay, it was reissued in 1970, 1996, and on the occasion of its 50th anniversary in 2012, as this fourth edition. This version presents a nicely packaged book that includes Kuhn’s 1969 postscript and a 30-page introductory essay by Canadian philosopher Ian Hacking.

In this book, Kuhn outlines how he thinks scientific knowledge advances, which goes something like this: a given scientific discipline is united under a certain paradigm (a collection of theories, research methods, standards etc. that define and delineate the field) and its practitioners engage in “normal science”: effectively solving puzzles by refining details of the paradigm and developing new methodologies to do so in the process. Inevitably, unexplainable anomalies start piling up until these can no longer be ignored. The field enters a state of crisis which is eventually resolved by a paradigm shift: a new way of seeing and understanding the world.

It pays to keep in mind that Kuhn was a physicist writing in the ’60s when this was one of the most influential scientific disciplines. The examples Kuhn has mined from the history of physics, chemistry, and astronomy are convincing examples of how we used to tackle certain questions in completely different ways that at the time had an internal logical consistency. This allows him to trot out movers and shakers in science such as Aristotle, Ptolemy, Newton, Franklin, and Einstein. Closer to home (for me) is geology which went from Lyell’s uniformitarianism to the rise and acceptance of plate tectonics and the role of catastrophes (see my reviews of Cataclysms, Four Revolutions in the Earth Sciences, and The Tectonic Plates are Moving!).

Kuhn writes many noteworthy things, of which I will highlight three.

First, looking at the history of science, the idea of unifying paradigms is fairly novel. In many fields, Kuhn mentions, there is a pre-paradigmatic period where everyone started from first principles and came up with completely different ideas to try and explain observations. But, one by one, paradigms started to form in these fields. This allowed scientists to all work under the umbrella of a shared understanding, resulting in refinement and the pursuit of ever more esoteric topics. These were then shared through specialised channels such as symposia and dedicated journals to the very limited audience of your peers. Incidentally, I wonder if this is when science retreated to its ivory tower.

Second, even if an old paradigm is increasingly becoming a creaking façade ready to tumble down, scientists will try and prop it up with ad hoc explanations, until a different paradigm is put forward that can be compared to both the old one and the observations done “in the wild”. Kuhn posits that the new paradigm is not necessarily better, might not explain certain observations the old paradigm did (or even deem them irrelevant), and often throws up its own questions. He even goes so far as to compare it to the blind process of natural selection which aims not towards an ultimate goal, but simply to survival in the here and now. So it is with scientific theories. But, when, on balance, the new paradigm seems to fit better, the slow and very human process of convincing and converting begins. Not surprisingly, young scientists usually come up with novel ideas, while the old guard steadfastly defends the ideas on which they build their careers, the old paradigm often dying when they do.

Third interesting point is that Kuhn feels the history of these revolutions has been largely hidden and forgotten. And he points the finger at textbooks. Being pedagogic tools written after the establishment of a paradigm, and with the aim of making students familiar with the current paradigm, they often only pay lip service to the long and complicated history of a field in an introductory chapter. As Kuhn writes nicely, this “truncates the scientist’s sense of his discipline’s history”. It also leads to the misconception that scientific disciplines advance linearly by accumulating more and more facts, theories and methods. Not so, says Kuhn surveying history: there are periods of crisis where the decks were swept clean, textbooks were rewritten, and groups of scientists started looking at problems through a completely different prism.

The introductory essay does a nice job of highlighting the book’s reception and the opposition of noted philosophers such as Karl Popper (biologists will know him from classics such as The Logic of Scientific Discovery and Conjectures and Refutations and the practice of hypothesis testing to accept or reject your proposed explanations), but also of interesting follow-up work looking at the book’s legacy such as The Road Since Structure.

Kuhn kept plugging away at his theory until the end of his life, leaving behind an unfinished manuscript on the question of incommensurability, i.e. whether the theories before and after a paradigm shift can be meaningfully compared to each other. He thinks not, as the way of thinking and the use and meaning of existing vocabulary have so dramatically changed that trying to read and understand classic scientific tracts can be almost impossible. This material was, and as of today still is, unpublished but in preparation. Look out for Thomas Kuhn: The Plurality of Worlds.

Although I will by default commend any publisher that goes to the serious* effort of continuing to make available classic works, my worry is always “how readable and relevant are they to a modern audience?”. Luckily, Kuhn’s well-crafted prose is still very readable today and his ideas remain intellectually stimulating. Interestingly, Hacking’s introductory essay already questions the applicability of Kuhn’s ideas to biology, which I will explore further in my review of How Scientific Progress Occurs.

* I am excluding the countless print-on-demand outfits churning out works of which the copyright has expired while adding zero value to them.