Thomas Kuhn’s Theory of Scientific Revolutions: Irrational Revolution or Continuation of Normal Science?

Christopher Nolan’s movie Interstellar discusses scientific revolutions and raises the question of whether Thomas Kuhn’s theory of scientific revolutions is an irrational revolution or a continuation of normal science. This article critiques Kuhn’s theory using examples from Darwin’s theory of evolution and 19th-century paleontology to discuss whether scientific progress is achieved through revolutionary change.

 

Christopher Nolan’s sci-fi movie Interstellar is all the rage these days. Interstellar is a sci-fi movie directed by Christopher Nolan about a group of NASA astronauts, including the protagonist, Cooper, who set out to find a new planet for humans to live on when food becomes scarce on Earth due to an extreme yellow dust storm. The reason why this movie has garnered so much attention is not only because of its enormous scale, which spans across our galaxy and other galaxies, but also because it introduces the concept of a fifth dimension that can be manipulated by humans, with time as one axis. In particular, the part where the surreal phenomenon of ghosts is explained as being created by humans who have fallen into the fifth dimension using the concept of gravity, a factor that is not affected by time, is thrilling.
In addition to its dramatic visual effects, Interstellar has also garnered attention for its visual representation of scientifically valid theories. The movie consulted with world-renowned physicist Kip Thorne to visually represent complex theories such as relativity, black holes, wormholes, and space-time distortion. The realism of this scientific backdrop makes Interstellar more than just entertainment for audiences, but an intellectual curiosity. It is a great example of how modern scientific theories can be utilized in movies, and the fusion of science and art is a refreshing shock to the audience.
In the movie, Cooper’s daughter finds a scientific answer to the surreal phenomenon of the fifth dimension by solving a new equation. Thomas Samuel Kuhn (1922-1996) saw the development of science as a revolution in the society of scientists to explain the phenomena that cannot be explained by the existing scientific theories in the modern era, and the arrival of a new era. His argument in The Structure of Scientific Revolutions led to a new way of looking at science by explaining historical examples that neither the inductivist nor the disproversialist could explain.
However, there are many questions about whether scientific progress actually occurs as revolutionary science. In this blog post, I will explain Thomas Kuhn’s argument to explain the development of science by dividing it into normal science and revolutionary science, and discuss the validity of his argument on two grounds.
Thomas Kuhn’s view of science focuses on the revolutionary nature of scientific progress. In other words, the revolution that triggers scientific progress consists of the abandonment of one theoretical structure and its replacement by another, incompatible theory. The independent systems that dominate at a given time, including these theoretical structures, are called paradigms, and the theoretical structures of science that emerge within a single paradigm are what Kuhn called normal science: the general theoretical assumptions and laws adopted by a community of scientists within a paradigm. Scientists working within normal science assume that the paradigm can provide solutions to problems posed within the paradigm, and a paradigm evolves as scientists working within normal science attempt to explain the world.
But because no paradigm can explain all of the behavior of things, scientists’ attempts to explain the behavior of things run into difficulties. This is called a crisis. To overcome this crisis, an entirely new paradigm emerges, and the crisis is resolved as more and more scientists believe in and accept the new paradigm and abandon the old one. Kuhn called this discontinuous change a scientific revolution. In the end, the progression of science is an iterative process of normal science → crisis → revolution → new normal science → new crisis.
Importantly, Kuhn’s process of scientific revolution is not simply the emergence of a new theory, but rather the acceptance of that theory by the entire scientific community. In this process, scholars who adhere to the old paradigm gradually become a minority, or are transformed into those who accept the new theory. This is an interesting perspective because it emphasizes that the development of science is not a simple logical progression, but is influenced by social and psychological factors. It also emphasizes that a paradigm shift is a holistic revolution that changes not only the scientific discovery, but also the academic and social context surrounding it.
Kuhn argues that paradigm shifts are akin to gestalt transformations or religious conversions, as members of a normal scientific community are drawn to the irrationality of the new paradigm.
However, I doubt that there is such a thing as an irrational scientific revolution as Thomas Kuhn claims. In the first place, I don’t think there is a conceptual disagreement wide enough to meet his criteria for a revolution. Kuhn was too deeply immersed in the dichotomy between normal and revolutionary science. Kuhn’s assertion that scientific progress did not occur through revolutionary change can be supported on two grounds.
The first is that the distinction between revolutionary change and normal small changes is very fuzzy. If we cannot distinguish between small changes and revolutions, then Thomas Kuhn’s argument for explaining the development of science by dividing it into normal science and scientific revolutions loses its logic. The distinction between revolutionary and normal change is really just a matter of degree: when is a small change normal to address anomalies within a paradigm, and when is it a revolutionary change? Kuhn does not provide a clear answer to these questions. As an example of this first point, let’s look at the history of paleontology in the mid-19th century.
One revolution in the field of paleontology in the mid-19th century was the theory of catastrophes. The theory of catastrophes emphasized the complete discontinuities found in geological artifacts and argued that these discontinuities were caused by supernatural events too violent to be explained scientifically. In other words, these discontinuities were evidence of a cataclysmic event that had never occurred on Earth before. This theory was supported by many scientists because it flies in the face of the existing paradigm, which holds that geologic change is always driven by the same kinds of forces and that Earth’s history has been one of repetition, and that discontinuities cannot be explained by this paradigm. Kuhn’s argument brought the old paradigm to a crisis, and many scientists began to shift to the new paradigm of tectonic catastrophism.
However, the discrepancy between the two paradigms has been narrowed by several pieces of evidence. First, Charles Darwin observed the results of an earthquake that changed the relative positions of geologic strata by as much as 20 feet in a single earthquake. Thus, the old paradigm gradually shifted to the idea that a single upheaval could create discontinuities. On the other hand, the normal scientists in the new paradigm found through their research that to explain the discontinuity, the upheavals had to be smaller in magnitude and more frequent than they had thought. Thus, they gradually came to believe that even dramatic upheavals were prolongations of geologic events. Eventually, the two paradigms gradually moved toward the other, meeting in the middle and showing that revolutionary upheavals were in fact a continuation of smaller fluctuations.
At the time, the theory of tectonic catastrophism was widely supported by scientists as a new paradigm that overcame the crisis of discontinuity facing the existing paradigm. However, as it turned out, cataclysms were just an extension of the small fluctuations that the old paradigm had suggested. Eventually, the line between cataclysms and small fluctuations became blurred, and scientific advances that we call revolutions were actually part of a series of small changes. The theory of tectonic catastrophism is a good way to point out the blurred line between revolutionary and normal science.
A second argument against Kuhn’s scientific revolution as a logical explanation of the history of science is that it is difficult to say that revolutionary changes occurred in isolation, without normal small changes. Scientific progress does not occur in a discontinuous manner through a single irrational revolution, but rather in a series of steps based on rational evidence. Even one big transition that appears to be an irrational revolution is only possible because of the vast amount of rational data and knowledge that has been accumulated. To demonstrate that scientific progress is not a single irrational revolution, but an accumulation of rational evidence, let’s look at Charles Darwin’s (1809-1882) theory of evolution and common descent.
Before Charles Darwin proposed the theory of evolution and common descent, the idea that all modern organisms descended from a common ancestor, there were many other scholars who argued for evolution and common descent. For example, around 600 BC, the Greek scientist and philosopher Anaximander argued that humans and other living things all descended from a common ancestor. However, the social context of ancient Greece at the time was unacceptable, and there was a lack of biological evidence to support this theory of evolution. Since then, the theory of evolution and common descent has been advocated constantly, but due to the lack of biological evidence, it has been rejected by the scientific community.
Then, at the age of 22, Charles Darwin joined the Royal Navy ship Beagle as a naturalist on a five-year voyage, during which he began to collect evidence to support the theory of evolution. Even after the five-year voyage, Darwin spent a whopping 20 years refining his opinions. This means that he had plenty of time to accumulate reasonable data and knowledge. After such a long period of research, Darwin published The Origin of Species, and from the numerous evidences presented in The Origin of Species, people began to accept the theory of evolution as a fact. Before Charles Darwin published The Origin of Species, the theory of evolution and common descent had already existed. However, the reason why previous evolutionary theories were not accepted until Darwin published The Origin of Species is that there was no rational evidence, whereas Darwin accumulated rational and scientific data for decades. In other words, Darwin’s theory of evolution and common descent was not a revolutionary transition to a new paradigm, but rather a transition to a new paradigm through inductive observation and the accumulation of rational data.
If scientific progress is the accumulation of evidence over a long period of time, Kuhn’s argument that a single irrational revolution causes a paradigm shift loses its logic. This idea of a gradual accumulation of observations leading to the formation of new concepts and eventually new laws blurs the line between normal science and scientific revolutions. In the end, the blurred line between major revolutions and normal change makes it questionable whether there is such a thing as a scientific revolution at all, and the second argument, that new laws are created through the accumulation of incremental observations, is a sweeping criticism of Thomas Kuhn’s distinction between normal science and scientific revolution. What we call revolutions are not irrational choices by scientists to solve a crisis, but rather new laws that emerge from the accumulation of progressive observations.
Thomas Kuhn’s “The Structure of Scientific Revolutions” is commendable in that it breaks away from the conventional view of science, which is that science advances by inductive observation or by finding new propositions by providing counter-examples to propositions, and moves towards a revolutionary new paradigm. However, I don’t think this is a logical argument. The distinction between revolutionary change and small change is a very blurry one. Rather, the relationship between revolutionary change and small change is a continuum. This blurring of boundaries is illustrated by the story of the history of paleontology in the mid-19th century. Furthermore, he argued that science does not develop in irrational revolutions, but rather in steps with a rational basis, and supported this with Charles Darwin’s theory of evolution and common descent.
In the past, political historians used to say that revolutions were easy to come by when confronted with violent events of political change, but it didn’t take long for them to realize that revolutions don’t actually involve such absolute and thorough breaks in continuity. Because no matter which revolution you look at, political continuities have been driving it. It seems to me that Thomas Kuhn’s distinction between scientific revolutions and normal science should be thought of in the same way. I wonder if revolutions in the development of science are nothing more than a series of small changes.