This blog post examines whether Kuhn’s paradigm theory can fully explain scientific development, exploring its limitations and complementary aspects through various case studies.

Introduction

Philosopher of science Thomas Samuel Kuhn explained how science progresses in his book ‘The Structure of Scientific Revolutions’. While disciplines like chemistry or geology align well with his theory of scientific development, I believe his theory has limitations in absolutely generalizing the process of scientific advancement. This is because his theory is difficult to apply precisely to certain scientific fields. This blog post aims to reveal the limitations of the ‘paradigm’ theory through examples from such fields and discuss ways to supplement it. First, using the examples of optics and evolutionary theory, it will show that multiple paradigms for interpreting a phenomenon can coexist. This will attempt to refute Kuhn’s claim that when two paradigms compete, one must inevitably be eliminated. Furthermore, using examples from mathematics and human biology, we will argue that there exist disciplines where the paradigm concept is difficult to apply. The goal of this article is to analyze the logical flaws in Kuhn’s theory of scientific revolution through this discussion and to propose points for its supplementation.

Main Discussion

Before critically discussing Kuhn’s theory, we will first briefly explain his theory of scientific revolution. Unlike the traditional view that science develops linearly, Kuhn saw scientific progress as proceeding nonlinearly. To explain this, he introduced the concepts of ‘normal science’ and ‘paradigm’. According to Kuhn, a paradigm is “a set of achievements recognized by scientists, serving as the foundation upon which further research is conducted.” In other words, a paradigm is the fundamental foundation upon which a particular scientific community believes facts to be true and conducts research. Normal science occurs within this paradigm, with scientists attempting to explain phenomena in accordance with it. However, Kuhn argued that when phenomena that cannot be explained by the paradigm accumulate, a crisis occurs, leading to a scientific revolution where a new paradigm, better able to explain these phenomena, replaces the old one. Thereafter, normal science unfolds again upon the new paradigm, and science progresses through the repetition of this process.
While describing the characteristics of scientific revolutions, Kuhn argued that choosing a paradigm is akin to choosing mutually incompatible political philosophies. Since two paradigms are usually incompatible, a paradigm shift—that is, a scientific revolution—occurs.
However, some cases in the history of science show that paradigm shifts do not always occur. The history of light’s nature can be seen as a counterexample to Kuhn’s claim that when two paradigms compete, one must be eliminated. In the early 18th century, Isaac Newton argued in his book Opticks that light possesses particle-like properties.
Simultaneously, Robert Hooke and Christiaan Huygens argued that light possessed wave properties. Thus, the paradigm of light as a wave coexisted with the paradigm of light as a particle. Despite making mutually incompatible claims about the same phenomenon, these two paradigms coexisted for two centuries. Without the wave theory, Thomas Young’s 19th-century double-slit experiment or James Clerk Maxwell’s research would have been difficult to achieve. Simultaneously, without the particle theory of light, Einstein’s photon theory would also have been hard to develop. Kuhn viewed this situation as a chaotic period where two paradigms coexisted, but dismissing two centuries of debate as mere chaos is an overstatement. It is more accurate to see the two paradigms—light as particles and light as waves—coexisting and each establishing its own normal science. Ultimately, the claim that light possesses dual nature as both particles and waves was adopted as the new paradigm, revealing that both paradigms had been meaningful discussions.
Evolutionary theory is another discipline demonstrating that multiple paradigms explaining a single phenomenon can coexist. While Darwin’s theory of natural selection is now accepted as the established view, it failed to explain the fundamental principle of natural selection when first proposed. The principle of natural selection was elucidated in the 1940s with the discovery of DNA’s molecular structure. This was a full 80 years after Darwin wrote ‘On the Origin of Species’ in 1859. During this period, competing theories such as Lamarckism, punctuated equilibrium, and directional evolution vied for acceptance. While these theories shared the common goal of explaining the phenomenon of evolution, they presented distinct perspectives on the evolutionary process. Consequently, it is difficult to view them as part of the same paradigm within normal science. Thus, discussions on evolutionary theory and the nature of light demonstrate that multiple paradigms can coexist to explain a single phenomenon.
To supplement Kuhn’s assertion that paradigms are mutually exclusive after a scientific revolution, it is necessary to revise the claim of the incommensurability of paradigms. Applying a pluralistic perspective could be a good alternative. That is, the relationship between paradigms is not one of elimination, but rather they can fuse or differentiate in ways that explain different phenomena. We must also consider that normal science can occur even when two paradigms coexist. This allows us to expand the scope of scientific history that Kuhn’s paradigm theory can explain.
Mathematics is a discipline where the limitations of applying Kuhn’s theory of scientific revolution become apparent. Mathematics develops through a deductive process, deriving new conclusions based on existing theories. For example, just as multiplication is defined based on the definition of addition, mathematics derives new conclusions from existing premises. Therefore, in mathematics, logical connections are more important than the entire paradigm. Consequently, defining a paradigm in mathematics holds little significance. Naturally, Kuhn’s theory of scientific revolution is difficult to apply here.
Human biology is also a field where clearly defining paradigms is difficult. For instance, before the invention of the microscope, humans could not observe the microscopic structures of organisms, so human research was conducted from a macroscopic perspective. After the microscope’s invention, cellular research began, followed by research at the molecular level. Research at the cellular level and research at the molecular level are mutually compatible; this can be seen as an evolution of research methods rather than a scientific revolution. The reason it is difficult to find a clear paradigm in human biology is that research methods differ and it is hard to find clear commonalities.
In conclusion, the examples of mathematics and biology show that there are fields where paradigms cannot be clearly applied. In such fields, it is more appropriate to explain progress as cumulative rather than forcibly applying Kuhn’s paradigm theory. Progress has been achieved by supplementing and developing existing theories.

Conclusion

Thus far, we have examined the limitations of Kuhn’s theory through the examples of optics, evolutionary theory, mathematics, and human biology. The cases of optics and evolutionary theory pointed out shortcomings in Kuhn’s claim that paradigms cannot coexist, proposing a pluralistic perspective as an alternative. The cases of mathematics and human biology demonstrated that there are fields where Kuhn’s theory does not apply, revealing that this is because the process of academic development is continuous. Kuhn’s theory offers a fresh perspective by viewing scientific progress not solely as the result of critical thinking, but also as arising from conformity to theoretical frameworks. However, it has limitations in explaining all developmental processes in the history of science. In fields where Kuhn’s theory does not apply, I believe it is necessary to seek new methods and adopt a complementary approach.