In this blog post, we explore whether scientific progress is the result of gradual accumulation or the product of revolutionary paradigm shifts.
Is scientific progress the result of continuous accumulation of research results? Most people would say yes without giving it much thought. And this was the prevailing view before Thomas Kuhn. However, when Thomas Kuhn published “The Copernican Revolution” and “The Structure of Scientific Revolutions,” a revolution occurred in our understanding of how science is done.
Of course, scientific activities are also carried out by accumulating research results based on already established theories and gradually expanding the realm of understanding. In fact, this is what most scientists do. This includes work to further refine standard theories in particle physics, attempts to calculate planetary motion using Newtonian mechanics, and the work of astronomers before the Copernican revolution. Science during this period is called normal science. Normal science is essentially no different from puzzle-solving. People who tackle puzzles and scientists are similar in that they know that there is an answer and they know the rules used to solve it. The rules used to solve puzzles can be said to correspond to paradigms.
Normal science is a process of solving detailed problems through stable and continuous research. Through this, we are able to accurately predict natural phenomena and make various technological advances in our daily lives. For example, the development of weather forecasting systems and communication technology is based on the achievements of normal science. The accumulation of normal science lays the foundation for humanity to gain a deeper understanding of nature, and in this sense, normal science plays a very important role.
However, according to Thomas Kuhn, truly creative and significant developments are achieved through scientific revolutions, not normal science. A scientific revolution refers to the process of replacing the existing paradigm of normal science with a new paradigm. Thomas Kuhn cites the Copernican revolution and the replacement of Newtonian mechanics with Einstein’s theory as representative examples.
During the course of normal science, phenomena or research results that do not fit well with existing theories often arise. This is the emergence of anomalies. However, the emergence of anomalies does not mean that all scientists abandon existing theories. Rather than considering anomalies as counterexamples to existing theories and abandoning the existing paradigm, they are regarded as unsolved puzzles, and the existing paradigm is adhered to. In many cases, these anomalies can be understood by applying existing theories. This is when the mystery is solved. In the geocentric theory, the retrograde motion of planets can be considered an anomaly. However, rather than questioning the belief that the Earth is stationary, the concept of a primary mover was introduced to explain the retrograde motion.
However, some serious anomalies cannot be easily explained within the framework of existing theories. This is when a crisis arises. Copernicus believed that it was impossible to explain the retrograde motion of planets by continuously introducing major and minor prime movers, and this can be seen as a crisis in the geocentric theory.
In crisis situations, some scientists break away from the existing theoretical framework and introduce a new theoretical system. This new theoretical system is still immature and not as accurate as the existing theory, but it provides a new perspective on the phenomenon. The birth of the heliocentric theory is an example of this. However, the languages of the two paradigms are different, so it is impossible to compare which one is superior. This is called incommensurability. Therefore, which paradigm to choose is entirely up to the individual scientist, and Thomas Kuhn even likens the process of choosing a new paradigm to religious conversion.
As time passes, new theoretical systems become more precise, and when the authorities of the scientific community who adhere to existing theories begin to step down, most scientists come to agree on the new paradigm. This process of reaching a consensus among the scientific community on a new paradigm can be called a scientific revolution.
However, there are also counterarguments to Thomas Kuhn’s claim. First, there is a question as to whether all science really develops from normal science to new normal science through scientific revolutions, as Thomas Kuhn claims. Examples of scientific revolutions cited by Thomas Kuhn include the Copernican revolution, the acceptance of the theory of relativity, quantum theory, the chemical revolution by Lavoisier, and Darwin’s theory of evolution. However, most of these examples fall within the realm of physics, and the content mentioned in the text is also mainly about physics. Considering that Thomas Kuhn began his studies as a physicist, it is understandable that he mainly explains physics, but it is unclear whether his explanation applies to other fields of science. In his book “This is Biology,” biologist Ernst Mayr pointed out that the concept of evolution had existed for a century before the publication of “On the Origin of Species” and that it had not been properly accepted even 100 years after its publication, arguing that there had been no period of normal science in biology. According to him, biology is fundamentally different from physics in terms of subject matter, history, methodology, and philosophy.
Furthermore, it is uncertain whether the Copernican Revolution, which is often cited as a representative example of revolution, was truly revolutionary. It took more than 100 years for the heliocentric theory to be proposed and fully accepted. Of course, the paradigm shift from the geocentric theory to the heliocentric theory was a huge event. However, the fact that it took so long for the paradigm shift to occur suggests that it was not so much a revolutionary change as a gradual accumulation somewhere between revolution and evolution.
Furthermore, Thomas Kuhn emphasized that due to the incompatibility between paradigms, the choice of paradigm by individual scientists cannot be based solely on rational criteria, but this may be an excessive criticism of science. Science is an activity carried out by scientists and their society, so it is natural that temporary irrationality appears during paradigm shifts. What is important is not the irrationality of that short period, but the steady rational development that occurs over a longer period of time.
Thomas Kuhn’s “The Structure of Scientific Revolutions” had such a profound impact on people’s perceptions that the term “paradigm” came to be used not only in the history of science, but also in the humanities, philosophy, and even everyday life. As Thomas Kuhn pointed out, there have been revolutionary changes in the history of science that cannot be explained by gradual accumulation alone. However, it is unclear whether these revolutionary changes were simply a series of events or whether the essence of science is development through revolutionary paradigm shifts. Furthermore, the irrationality of the scientists and scientific community he mentioned is inevitable as long as we are human, and what is important is that science continues to develop steadily despite such irrationality.
