This blog post critically examines how Thomas Kuhn’s philosophy of science influenced scientific progress and research methods.
When discussing the philosophy of science since the 20th century, Thomas Kuhn and his book ‘The Structure of Scientific Revolutions’ are indispensable. By introducing the concept of the paradigm, Kuhn explained that all scientific activity—including understanding, conjecture, and research—occurs within a fixed cognitive framework, and that science progresses not through the accumulation of knowledge but through paradigm shifts. His theory conflicts with the traditional view of science, which has emphasized falsificationism or the accumulation of knowledge. Contemporary scholars were critical of Kuhn’s theory, even holding symposiums to discuss it. Some believed his theory viewed scientific progress too extremely, fostering blind faith in paradigms and stifling critical thinking. Indeed, his philosophy of science theory is somewhat conservative or lacking in rigor, as it accepts paradigms as established truths and relies on trust rather than verification. However, accepting his theory and viewing science from that perspective can be highly beneficial for scientific research. This article focuses on Kuhn’s philosophy of science, discussing the constructive influence his theory has on scientific research and the appropriate attitude toward it.
Understanding Kuhn requires a prior grasp of the concept of paradigms. Unfortunately, he used this term quite ambiguously in The Structure of Scientific Revolutions, making it difficult to grasp its meaning definitively. Synthesizing his other works and interpretations of him, the general meaning of paradigm he intended appears closer to the term’s original sense of ‘preface’ or ‘introduction’. Just as a book’s introduction typically informs readers about its content or writing method, Kuhn argues that a paradigm serves as a scientific ‘model’ presenting specific theories and methods for explaining phenomena. The geocentric model is a suitable case for understanding this. Before the heliocentric theory emerged, all scholars believed in the geocentric theory and understood and explained all astronomical phenomena based on it. In this sense, it was the paradigm for understanding astronomy of that era.
Scientists accepted the paradigm of their era as established doctrine, conducting all scientific activities—including research and problem-solving—based on it. Kuhn defined this behavior as normal science within a paradigm. It involves observing and understanding all scientific phenomena based on the paradigm and solving the problems the paradigm presents. If the heliocentric theory is the paradigm, then normal science is understanding and explaining all phenomena based on that heliocentric theory. The problems presented by the paradigm refer to issues that were previously unaddressed but whose outcomes can be predicted through the paradigm, or problems that must be solved for the paradigm to become more sophisticated. Kuhn also likened normal science to ‘puzzle-solving’ because scientists conduct all scientific activities solely within the framework presented by the paradigm.
However, since a paradigm is not ‘fact’ but rather a kind of accepted framework of its time, one cannot be certain that all scientific phenomena existing in the universe fit within that framework. Kuhn suggested that as counterexamples not explained by the paradigm gradually accumulate, the existing paradigm becomes threatened. If this threat persists, a new paradigm (hereafter ‘new paradigm’) emerges to explain the counterexamples, placing the new paradigm and the existing paradigm (hereafter ‘old paradigm’) in a competitive relationship. At this point, the two paradigms enter a state of incommensurability. The two incommensurable, competing paradigms undergo mutual verification by scientists, and only the paradigm that wins the verification process survives. At this point, the old paradigm is discarded and the new paradigm replaces it, allowing normal science to proceed. Kuhn defined this phenomenon as a ‘Scientific Revolution’ and argued that scientific progress is a discontinuous revolution driven by incommensurable paradigms.
Adopting Kuhn’s philosophy of science and viewing science from this perspective offers advantages in scientific research. First, normal science adopts a fairly comprehensive stance in the pursuit of truth. Generally, discussions about truth divide into realist and anti-realist positions. Scholars expressing a realist position believe that truth must not only describe observable facts and possess empirical validity in predicting new phenomena, but also be capable of perfectly explaining even unobservable aspects. Conversely, anti-realists consider discussions about unobservable content meaningless. This is not mere skepticism but a pragmatic stance against setting unattainable goals. The truth Kuhn pursues is grounded in anti-realism but does not reject realism. The paradigm of normal science is a cognitive system created to encompass all previously discussed scientific concepts and theories. Consequently, it is constructed solely on the basis of previously discussed, i.e., verified scientific phenomena, and does not consider scientific phenomena that have not been previously discussed, i.e., unverified ones. In this respect, it can be said to be grounded in anti-realism. On the other hand, once a paradigm is accepted as normal science, it attempts to explain all scientific phenomena based on it, including even unobservable aspects. Therefore, it can be seen as partially reflecting the direction of truth pursuit desired by realism. This makes it a somewhat loose concept when strictly compared to realist truth and anti-realist truth. This is because it claims to explain even unobservable content, despite the difficulty of verification, based on theories concerning historically discussed and confirmed aspects—that is, the content that anti-realism asserts as truth. Such a definition of truth satisfies a higher level of accessibility in scientific research, as it does not reduce the domain of truth while simultaneously meeting the practicality required in scientific inquiry. String theory is an appropriate case to illustrate this.
String theory is a theory capable of explaining not only the interactions and fundamental particles of interest in modern physics, but also everything currently explainable within the paradigm of physics. Furthermore, it can explain the realm of the unobservable quantum. However, the reality is that even scholars who study and advocate for it acknowledge that direct observation of strings, the fundamental elements of string theory, is effectively impossible. This falls short of being considered truth when strictly adhering to both realist and anti-realist positions. However, viewed from Kuhn’s perspective, it perfectly explains all known facts to date, thus lacking any disqualifying flaws as a paradigm of normal science. In other words, accepting it based on Kuhn’s position allows for realistic research without narrowing the domain of truth. This facilitates easier access to scientific research. In other words, it enhances the efficiency of scientific inquiry.
Normal science also clearly indicates the direction natural science should pursue. Generally, researching natural science means exploring the scientific theories and concepts that constitute this world. However, the greatest problem here is the very existence of these theories and concepts. The existence of the subject matter to be researched must be assured before research goals can be established, yet this assurance is difficult to achieve. Normal science provides scientists with research subjects and corresponding objectives based on a paradigm. Accepting a paradigm means accepting it as established doctrine. Therefore, all scientific phenomena must be explainable based on the paradigm, and results predicted by the paradigm’s theories—even if not yet confirmed—must actually exist. In other words, the paradigm guarantees both the explainability and the existence of these phenomena, making research possible.
The recently discovered gravitational waves exemplify this. Based on the theory of relativity, gravitational waves are necessarily an observable phenomenon. However, their existence remained unconfirmed until Einstein, who proposed relativity, passed away. Physicists, including Kip Thorne, systematized the phenomena that should be observed when gravitational waves occur based on relativity theory and built LIGO, the facility capable of detecting them. Ultimately, the LIGO research team announced the discovery of gravitational waves in 2016 and was awarded the 2017 Nobel Prize in Physics for this achievement. This approach might be considered somewhat risky, as the validity of the underlying theory remains unproven. However, if we were to deny the validity of all scientific research simply because the underlying theory—the paradigm—has not been proven, humanity’s quest for truth would remain stagnant until the foundational theories were validated. Furthermore, such scientific approaches themselves might never have materialized. From this perspective, normal science contributes to accelerating scientific research by providing a roadmap.
We have examined Kuhn’s philosophy of science and its significance for scientific research. Kuhn’s philosophy defined the cognitive norm of the paradigm and presented normal science within it. It also explained scientific progress not as the accumulation of knowledge but as the replacement of paradigms. While this approach drew criticism from many scholars, it is evaluated as having broadened the spectrum of philosophy of science and exerted considerable influence not only within the philosophy of science community but also in the natural and social sciences. As discussed earlier, embracing his philosophy of science has contributed to the efficiency of scientific research in terms of truth-seeking and research direction, and will continue to do so. However, the risks inherent in Kuhn’s philosophy of science, which has faced criticism, must also be fully considered. Considering all these points, we can see that we should view his philosophy of science through an efficiency-oriented lens. Rather than simply condemning and rejecting his theory, we should accept its positive impact on scientific activity while maintaining a critical attitude toward the potential dangers it may pose. If we embrace his philosophy of science from this perspective, I believe it will greatly contribute to advancing scientific research by enabling a rational approach to it.
