The Structure Of Scientific Revolutions
Reviewing the classic of Thomas Kuhn
If you’re interested in science or philosophy, you may have heard of Thomas Kuhn. And if you happen to have an interest in both, he almost has mythical status. Until then, philosophy of science was mostly based on Popper’s ideas of falsification. But that view, while important, faded into the background after Kuhn’s publishing of this book in 1962. I’ve finally decided to give the original book a shot, without knowing if it would be worth it, given that I already knew a general idea.
The main theme is fighting against a view of continual scientific progress. A somewhat linear, ever-accumulating list of facts that lead up to where we are today. This is view is still incredibly common now, even among scientists. This is largely what prompted me to dig deeper into the idea. Despite the incredible popularity and success of Kuhn’s work, it seems to have remained more in philosophy than in science, and sometimes it seems the world has moved on without taking its insights seriously.
He distinguishes two modes of scientific endeavours. One is normal science, which is the typical view, and the other is a scientific revolution. Normal science is done when the paradigm is stable. Its assumption is so strong that it can hardly be understood how it can be otherwise. This is not only an accepted theory of how the world works, which impacts the perception of how the world works but also impacts the perception of how we ought to further gain knowledge about how the world works. It is a shared cognitive framework with a specific set of values, tools, methods, techniques, and so forth. In this normal mode, science tends to develop its paradigm, to dig deeper, and add detail. This is its main counterpoint to Popper. Falsification sounds like the correct approach in an abstract philosophical mode of conducting science, but Kuhn describes how science is actually done in the real word. Rather than trying to prove something wrong, most science is done to add details and further clarification.
However, in this process of normal science, often abnormalities appear. All paradigms have abnormalities, phenomena that do not fit into our model, including today’s paradigms in many fields. These are often brushed aside with posthoc rationalizations or hoped that are irrelevant, and we will later be able to fit the abnormality into our model in the future with better methods or technology. However, when such abnormalities start to accumulate, and especially if a pattern starts to emerge in them, the stability of the paradigm starts to shake. In this situation, the paradigm itself starts to be questioned, and the fundamentals are revised.
Extraordinary research tends to be conducted in which the goal isn’t only to add detail to the accepted paradigm, with its scope being much wider and less traditional. Philosophy is revived and works along with science. Alternative paradigms are proposed and they fight against each other. The paradigm that can explain the most abnormalities and make the best predictions eventually comes to the accepted paradigm — a scientific revolution. This is the second-way science operates, a completely different mode than the normal science previously covered. The change of paradigm is hardly a soft transition, however. They are often fiercely opposed for a long time, and scientists tend to hold on to the previous paradigm as much as possible. As Max Planck said: “a new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.”
After a scientific revolution, normal science resumes. This is why it is hard to recognize it because we generally only tend to live in a period of normal science, and revolutions of the past are not emphasized. Even if not explicitly, they are often not perceived as revolutions at all but incorrectly as simply significant points of the accumulation of knowledge. Kuhn claims this is often reinforced by textbooks, which have the practical goal of teaching students the methods and knowledge needed to participate in the normal science they are about to enter. Therefore, history is of little importance, and many scientists go through their education without knowing the historical turmoils of their field. He does not condemn this per se since it has little practical value of students to know it, but it nevertheless provides a false impression of how science has progressed.
Kuhn gives several examples of scientific revolutions: from a Ptolemaic cosmology to a Copernican one, Aristotelian mechanics to classical mechanics, Euclidian to non-Euclidian geometry, Lavoisier’s theory of chemical reactions, Newtonian gravity to general relativity, and others. The important point that is often missed, even by people familiar with Kuhn’s idea of scientific revolutions, is that these aren’t discoveries of just new knowledge. They are complete overthrows of worldviews in their specific domains. How scientists think, view the world, and conduct research is completely new.
My favourite example from the book is how people viewed pendulums. With an Aristotelian paradigm, it was viewed as if the object was falling (given it is its nature to do so), but it was constrained by the chain or string. Therefore, its swinging is a falling motion. With a Galilean paradigm, however, it is a different phenomenon entirely. Galileo saw a body almost succeeding in repeating the same motion over and over again, but unable to do so and eventually stopping. They are the same phenomenon but vastly different interpretations. This is more relevant than it initially seems, as it affects how you research such phenomena. You generally don’t measure variables that you don’t consider relevant, and what you consider relevant depends on your a priori interpretation of the phenomena.
This perception element of scientific frameworks is one of the biggest takeaways from his work and is often missed, despite being explained in-depth in the book. Many of the criticisms that naive scientists make against a revolutionary view of scientific progress are addressed in the original work itself, half a century ago.
About the book itself, beyond Kuhn’s ideas, I have mixed feelings. On the one hand, I felt it dived into details that aren’t commonly known even to those aware of the concept of scientific revolutions. On the other hand, the message could have been better delivered. While the writing is good, the content often feels repetitive. For example, Newton’s Principia or Lavoisier’s Elements are mentioned dozens of times. Even odder, considering how the author keeps mentioning that many other examples could have been made but that he would not have the time to go in-depth into them. Yet he repeats the same ones to emphasize the same point over and over again. I felt that this could have been vastly improved. Nevertheless, it was still a great read. Even if you’re familiar with his work, you will get some extra insights, and if you’re not, then you’re in for a treat.
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Tiago V.F.
