This blog post examines whether the concept of normal science in Thomas Kuhn’s theory of scientific revolution truly excludes criticism and only shifts paradigms during crises.
Thomas Kuhn, a philosopher of science who coined the new concept of ‘paradigm,’ defined it in The Structure of Scientific Revolutions as “a total framework or set of concepts that combines scientific knowledge, theories, conventions, thinking, ideas, and values dominating an era.” Specialized research activities grounded in a specific paradigm are termed normal science. Such normal science inherently suppresses novelty because it attempts to fit research subjects into the framework provided by the paradigm. This is also the most fundamental characteristic of normal science. Kuhn argues that the existing conception of science was formed precisely by this nature. He contends that the search for a new paradigm only begins when the existing paradigm can no longer avoid anomalous phenomena that disrupt the tradition of scientific activity. In summary, Kuhn states that normal science does not aim for novelty in facts or theories, and critical discussion only occurs when the paradigm ceases to function effectively. Since explanations of history, including the history of science, require accurate factual understanding, it is necessary to verify whether Kuhn’s explanation can be justified. The author will describe what Kuhn means by “scientists engage in critical discussion only during crises,” introduce Feyerabend’s rebuttal, and also critique aspects Feyerabend did not address.
To properly understand Kuhn’s explanation, it is necessary to accurately grasp the concepts of ‘crisis’ and ‘critical discussion’. A scientific revolution signifies the event where the period of normal science ends and a paradigm shift occurs. Kuhn explains that research proceeds without a paradigm, a paradigm is established, and the period of normal science is maintained until anomalous cases emerge, placing the paradigm in crisis. Subsequently, the process of transitioning from the existing paradigm to a new paradigm unfolds. The anomalous cases that cause the crisis are phenomena that cannot be explained by normal science, despite being activities conducted within normal science. To solve significant problems among these anomalous cases, normal scientists relax the problem-solving rules and use auxiliary hypotheses. Kuhn states that during this process, the paradigm becomes ambiguous and the rules of normal science become lax, marking the beginning of the ‘crisis’.
To accurately understand Kuhn’s position on ‘critical discussion,’ one must focus on how he explains the concept of a paradigm. Kuhn argued that without a shared belief system (paradigm) that can be taken for granted, scientists would have to attack the fundamental principles of other schools of thought while asserting and justifying their own principles. He believed that conducting such activities without fundamental agreement constituted philosophy, not science. Consequently, he concluded that the beginning of science is the cessation of critical discussion about its basic principles. That is, when a mainstream paradigm exists, one should not question its fundamental principles regarding research conducted within it. The ‘critical discussion’ of a paradigm’s fundamental principles that Kuhn speaks of is ultimately the same ‘critical discussion’ needed to create alternative theories. This is because competing paradigms differ fundamentally in their basic principles. For example, when the speed of light is very small, the laws of relativity appear in equations similar to Newton’s laws, but the meaning of ‘mass’ is completely different in the two theories. The reason Dalton and Berthollet’s dispute over the definition of compounds persisted was also because their ways of defining compounds differed. Since the most fundamental concepts of the two competing paradigms are different, an alternative theory cannot be created without critiquing the basic principles. Ultimately, it becomes clear that the ‘critical discussion’ of fundamental principles, as Kuhn envisions it, must precede the generation of alternative theories. Having grasped Kuhn’s position on ‘crisis’ and ‘critical discussion,’ we now introduce Feyerabend’s rebuttal to Kuhn’s explanation.
Feyerabend is a prominent figure who challenged Kuhn’s concept of normal science. He criticizes Kuhn’s normal science, which raises barriers to entry into science and achieves specialization through paradigm formation, arguing that Kuhn’s concept of normal science is a form of expertism and that normal science is inappropriate as a methodological prescription. The criticism that normal science possesses dogmatic characteristics was a controversial point even raised by Kuhn himself. In response, Kuhn explained that the uncritical acceptance of normal science merely provides the ‘framework’ within which scientists can think. He countered that to call normal science dogmatic, it should be “criticizable but not criticized,” but in reality, criticism itself is too difficult, making it “uncriticizable,” and thus not dogmatic. He presents examples where provisional hypotheses led to new discoveries while dogmatically protecting a specific paradigm, showing the positive aspect of persistence in adhering to a theory. Even Feyerabend acknowledges that theories should not be easily discarded, as it is difficult to readily judge their potential for development or improvement, and one cannot ignore the possibility of errors in experimental results or observations, or delays in the progress of auxiliary sciences.
However, Feyerabend argues that this approach cannot eliminate any anomalous cases from the existing paradigm. He contends that insisting on a single theory cannot achieve a paradigm shift, necessitating the ‘principle of proliferation’—the constant existence of alternative theories. For alternative theories to exist during a crisis, they must have been created beforehand, during the period of normal science. This requires attempts to solve problems using methods other than the existing paradigm. Ultimately, critical discussion of the existing paradigm during the period of normal science is necessary for a scientific revolution to occur.
Furthermore, Feyerabend contends that Kuhn’s explanation that “critical discussion only occurs during crises” does not align with actual history. In the 19th century, three incompatible paradigms coexisted: the mechanistic viewpoint, the phenomenological theory of heat, and Faraday and Maxwell’s electromagnetism. Feuerabend contends that active interaction actually existed between these three paradigms. Without such interaction, had each paradigm focused solely on solving puzzles within itself, the inquiries that led to the relativity revolution, quantum revolution, and statistical revolution would not have occurred. From Kuhn’s perspective, such cases might be considered highly exceptional. However, Feyerabend contends that even if such explorations were the work of a minority, it was not puzzle-solving but the activities of these few scientists crossing paradigms that produced major scientific progress. This implies that Kuhn’s explanation, which temporally separates revolution (periods of proliferation) from normal science (periods of monistic scientific activity), has failed. Ultimately, revolution was possible precisely because critical discussions occurred even during periods of normal science.
Beyond being logically impossible and inconsistent with actual history, as Feyerabend demonstrates, Kuhn’s argument has additional flaws. First, when a crisis arises, one cannot be certain it is indeed a crisis. When unable to resolve anomalous cases within normal science, normal scientists attempt to protect the paradigm by relaxing problem-solving rules or introducing auxiliary hypotheses. This process makes consensus on the paradigm’s scope impossible, leading to its obscuration. Kuhn asserts that “all crises begin with the obscuration of a paradigm and the consequent loosening of the rules of normal science.” However, ‘ambiguity’ and ‘laxity’ are phenomena lacking clear criteria, meaning the moment each scientist perceives as a crisis may differ. Paradigms enabled continuous research by presenting problems to be solved and rules to follow. Therefore, anomalous cases inevitably continue to emerge, but this does not mean every such moment constitutes a crisis for the paradigm. This is because normal science itself is the activity of solving anomalous cases as puzzles. According to Kuhn’s argument, competing paradigms possess incommensurability, meaning a ‘crisis criterion’ applicable to both paradigms cannot exist in the first place. In other words, whether a specific anomalous case is perceived as a crisis depends on perspective. Kuhn argues that crises serve as indicators signaling when tools (paradigms) must be changed, but we cannot be certain that crises actually fulfill this role.
Kuhn’s explanation regarding the historical role of science can also be challenged. Examining Popper’s critique, Popper states:
The “normal scientists” Kuhn speaks of are poor souls indoctrinated with dogmatic mindsets. Their attitude poses a threat not only to science but to our civilization itself.
Just as Newton’s mechanical clock view greatly contributed to the Enlightenment, science has played a crucial role in replacing God with reason. The notion that science can enlighten and advance society is a common belief, and indeed, science has fulfilled this role. Therefore, Kuhn’s claim that scientists only engage in critical discussion during paradigm crises is difficult to accept. This is because the role of science does not change merely because it is a period of normal science. For science to perform this role, critical discussion must have occurred at all times.
The final issue with Kuhn’s explanation of critical discussion during crises relates to his phrasing. In The Structure of Scientific Revolutions, Kuhn presents the above explanation while also asserting that “critical discussion should only occur during crises.” Specifically, within a single paragraph, Kuhn presents both the following explanation and assertion:
The invention of alternatives is a task that scientists rarely undertake in the development of science, except during the pre-paradigm stage, and it occurs only in extremely special cases during the subsequent process of advancement.
Like in productive activities, creating new extensions of science is a kind of luxury prepared for when it is demanded.
The above sentence is closer to an ‘explanation’ that the creation of alternatives occurs almost exclusively during crises, while the following sentence appears to be Kuhn’s personal view that changing tools during non-crisis periods is a luxury. Of course, given that Kuhn pioneered the new field of historical philosophy of science, one might expect his stance on this topic to lean more toward an explanation of ‘what happens’ or ‘what has happened’ rather than a claim of ‘what ought to happen’. However, there remains a sense of regret that Kuhn did not present his arguments with greater clarity and consistency.
While Kuhn explains that new theories emerge only after significant failures in normal problem-solving activities, it is clear that for a scientific revolution to exist, critical discussions must occur even during periods of normal science, according to Feyerabend’s ‘principle of proliferation’. Furthermore, actual history does not support his explanation. Furthermore, considering the inability to confirm a crisis during a crisis and the role of science, I was able to refute Kuhn’s explanation. This process led me to conclude that Kuhn’s account of the history of science is flawed. If, as Kuhn suggests, scientists only engaged in critical discussion during crises, one might conclude that since scientific progress still occurred, critical discussion could continue to be confined to crisis periods. However, this is a highly dangerous notion. If we were to adopt a flawed paradigm, like the now-discredited alchemy or geocentric theory, the absence of critical discussion would delay the revolution, prolonging the time spent stuck there. Consequently, much research could ultimately prove futile. To prevent such hypothetical scenarios arising from Kuhn’s inaccurate portrayal, an accurate explanation of the history of science is essential.
