In this blog post, we explore whether scientific progress is the result of gradual accumulation or the product of revolutionary paradigm shifts.
Is the advancement of science the result of the continuous accumulation of research findings? If you haven’t thought deeply about this topic, most people would probably say yes. And this was the prevailing view before Thomas Kuhn. However, when Thomas Kuhn introduced the “Copernican Revolution” and “The Structure of Scientific Revolutions,” a revolution also occurred in our understanding of how science is conducted.
Of course, scientific activity also involves accumulating research findings based on established theories and gradually expanding the realm of understanding. In fact, most of the research conducted by scientists falls into this category. Examples include efforts to further refine the standard theory in particle physics, attempts to calculate the motion of planets 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. Both puzzle solvers and scientists are similar in that they know that answers exist and that there are rules for solving puzzles. The rules used to solve puzzles can be considered paradigms.
Normal science is a process of solving detailed problems through stable and continuous research. Through this process, we are able to accurately predict natural phenomena and achieve various technological advances in our daily lives. For example, the development of weather prediction systems and communication technology is based on the achievements of normal science. The accumulation of normal science provides a 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 not through normal science but through scientific revolutions. A scientific revolution refers to the process by which the existing paradigm that forms the framework of normal science is replaced by a new paradigm. Thomas Kuhn cites the Copernican Revolution and the replacement of Newtonian mechanics by 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 emerge. This is the appearance of anomalies. However, the emergence of anomalies does not mean that all scientists abandon existing theories. Instead of viewing anomalies as counterexamples to existing theories and abandoning the existing paradigm, they are seen as unsolved puzzles, and the existing paradigm is maintained. In many cases, these anomalies can be understood by applying existing theories effectively. This is what we call solving the puzzle. For example, the retrograde motion of planets could be considered an anomaly in the geocentric model. However, rather than questioning the belief that the Earth is stationary, scientists introduced the concept of epicycles to explain the retrograde motion.
However, some serious anomalies are difficult to interpret 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 larger and smaller epicycles, and this can be seen as a crisis of the geocentric model. In a crisis situation, some scientists break away from the existing theoretical framework and introduce a new theoretical system. This new theoretical system is still immature and lacks the accuracy of the existing theory, but it provides a new perspective on phenomena.
The birth of the heliocentric theory is an example of this. However, since the languages of the two paradigms are different, it is impossible to compare which is the superior paradigm. This is called incommensurability. Therefore, the choice of which paradigm to adopt is entirely a matter of personal preference for each scientist, and Thomas Kuhn even compared the process of choosing a new paradigm to religious conversion.
As time passes, new theoretical systems become more precise, and as the authorities who adhered to the existing theories begin to step down, most scientists come to agree on the new paradigm. This process of reaching consensus within the scientific community on a new paradigm is what we call a scientific revolution.
However, there are also counterarguments to Thomas Kuhn’s claims. First, there is doubt as to whether all science truly develops from normal science to a new normal science through scientific revolutions, as Thomas Kuhn suggests. Examples of scientific revolutions mentioned 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. Biologist Ernst Mayr, in his book “This Is Biology,” pointed out that the concept of evolution existed a century before the publication of “On the Origin of Species” and was not properly accepted even a century after its publication. He argued that there was 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, often cited as a prime example of revolution, was truly revolutionary. It took more than a century for the heliocentric theory to be proposed and fully accepted. Of course, the paradigm shift from the geocentric to the heliocentric theory was a monumental event. However, the fact that such a long time was required for the paradigm shift suggests that it was more of a gradual accumulation than a revolutionary change.
Furthermore, Thomas Kuhn emphasized that scientists’ choice of paradigm is not based solely on rational criteria due to the incompatibility between paradigms, which may be an excessive criticism of science. Since science is an activity carried out by scientists and their society, it is natural for temporary irrationality to appear during a paradigm shift. What is important is not the irrationality of that short period, but the steady rational development that appears over a longer period of time.
Thomas Kuhn’s “The Structure of Scientific Revolutions” had a profound impact on people’s perceptions, extending the use of the term “paradigm” beyond the history of science to the humanities, philosophy, and everyday life. As Kuhn pointed out, the history of science has witnessed revolutionary changes that cannot be explained by gradual accumulation alone. However, it remains unclear whether these revolutionary changes were merely isolated incidents or whether the essence of science lies in its development through revolutionary paradigm shifts. Additionally, the irrationality of scientists and the scientific community that he mentioned is an inherent aspect of human nature, and what is important is that science continues to develop steadily despite such irrationality.
