This blog post examines whether Thomas Kuhn’s paradigm theory can serve as a useful framework for explaining scientific progress or if it is a concept riddled with internal contradictions.
Thomas Kuhn’s The Structure of Scientific Revolutions holds a significant place in the history of philosophy of science, and his theory has sparked considerable debate. The differing interpretations held by participants in the debate surrounding this book are so divergent that it is hard to believe they all read the same book, likely due to the interpretive flexibility inherent in its content. The fundamental reason for this flexibility lies in the introduction of the term ‘paradigm’. This diversity of interpretation leads critics to attack Kuhn’s theory from different angles.
In The Structure of Scientific Revolutions, Kuhn explains paradigm shifts by comparing two paradigms that describe the same phenomenon, albeit often in different ways, using various examples from science. However, while he asserts the incomparability of paradigms through incommensurability, he simultaneously appears to compare paradigms when necessary. This seems inconsistent. Alongside the categorical ambiguity of paradigms as Kuhn argues, we will examine the contradictions that emerge in explaining the paradigm theory through ‘incompatibility, incommensurability, and translatability’.
In The Structure of Scientific Revolutions, Kuhn explains how science has developed. When anomalous cases persistently appear within an established normal science, and the number of cases that cannot be explained by the existing normal science gradually increases, doubts are raised about the existing paradigm, and a crisis befalls normal science. To resolve this crisis, a new theoretical framework is proposed. Through further research, a scientific revolution occurs where the new framework replaces the old paradigm, and science advances as a new normal science becomes established.
Kuhn’s ‘normal science’ refers to research firmly grounded in one or more scientific achievements. Here, ‘achievements’ denote accomplishments recognized by a specific scientific community over a period as the foundation for future research. These achievements, though not in their original form, are listed in elementary or secondary science textbooks. These textbooks explain a series of established theories, illustrate them with successful application examples, and present experimental examples. For instance, university physics textbooks present theoretical explanations and verifiable cases and experiments based on Newton’s classical mechanics, and address application problems.
Aristotle’s Natural Philosophy, Ptolemy’s Almagest, Newton’s Principia and Opticks, Franklin’s electricity, Lavoisier’s chemistry, and Lyell’s Principles of Geology all served to define legitimate problems and methodologies within the research of past scientists. These achievements were sufficiently outstanding to form a community of followers that excluded competing scientific research approaches, and sufficiently open to present diverse problems to newly formed researchers. Kuhn termed such achievements possessing these two characteristics a ‘paradigm,’ which is closely associated with ‘normal science’.
A scientific revolution possesses three characteristics: incompatibility, incommensurability, and untranslatability. First, incommensurability means that problems previously seen as trivial can become prototypes for significant scientific achievements with the emergence of a new paradigm. As problems change, the criteria for finding scientific answers can also shift through metaphysical reasoning, changes in terminology, or mathematical manipulation. The normal scientific tradition emerging from a scientific revolution is often incompatible with the previous one and cannot be compared using the same standards. Incompatibility means that theories explaining the same natural phenomenon differ before and after a scientific revolution and cannot coexist. Finally, untranslatability signifies that incompatible and incommensurable theories cannot be translated into each other. For example, Ptolemy’s geocentric model and Copernicus’s heliocentric model can both explain the Earth’s day and night, but they embody fundamentally different perspectives.
In The Structure of Scientific Revolutions, Kuhn argued that two paradigms are incompatible and incomparable due to differing worldviews and tools used, thus rendering them non-commutable. However, regarding non-commutability, comparability, and communicability, he seems to leave some room for evasion by suggesting the impossibility is local rather than total. This can be interpreted metaphorically as ‘the absence of a common language’. It means that while most common terms between two paradigms retain their meaning, some terms undergo semantic shifts, making translation difficult. Incommensurability thus represents a softened position, meaning that statements from the two theories cannot be translated into neutral language without distortion.
Regarding the criticism that “incommensurability is untranslatability,” Kuhn responded by comparing the translation process to language acquisition, arguing that understanding an incommensurable paradigm is not translation but a process akin to language acquisition. This difference arises from whether one knows both languages, and what is needed to understand another paradigm is step-by-step learning, like the process of learning a language. This appears to be a somewhat softened position compared to his earlier assertions of incompatibility and incomparability.
Among Kuhn’s critics, Scheffer and Scheffler criticized his theory as follows. Scheffer viewed various biases as hindering the objective judgments scientists should make, arguing that removing these biases is the role of sociology, and thus criticized Kuhn’s perspective. Scheffler similarly pointed out that no compelling reason was presented to deny objectivity in the process of critically evaluating scientific theories, criticizing Kuhn for introducing into his conclusion the very concept he sought to negate in his discussion. Scheffler argued that Kuhn’s mentioned criteria—predictive power, the existence of anomalous cases and crises, and the preservation of problem-solving ability—contradict the thesis that paradigm shifts in science do not occur through critical evaluation.
A common point raised by Kuhn’s critics is that while paradigms are scientific frameworks distinct from reality, Kuhn describes the relationship between frameworks in a contradictory manner. However, the paradigm Kuhn later revised and mentioned after The Structure of Scientific Revolutions differs somewhat. If a paradigm were merely a formal framework for understanding science, it would indeed be distinct from reality. The argument is that the way scientists perceive the world involves more than a formal framework. Two uses of ‘paradigm’ are as follows: First, ‘paradigm’ encompasses the shared assumptions of a specific scientific community. Second, it carries the meaning of partially isolating specific assumptions. Isn’t it problematic to transform and apply this ambiguously defined paradigm whenever it seems necessary in the process of scientific development?
Furthermore, in Kuhn’s theory, the question arises regarding how far to extend the category when explaining past and subsequent theories. Applying the paradigm theory to each scientific theory requires considerable effort. Considering that explaining phenomena with a simple theory is likely closer to truth, Kuhn’s paradigm theory for explaining scientific development seems unsuitable.
In this way, by comparing and explaining paradigms that are incommensurable and incomparable, and by using the contradictory term “local holism,” Kuhn avoids direct attack. Using ambiguous and ambiguous expressions to make rebuttal against falsification and counterexamples difficult seems to contradict the logic that the better the scientific theory, the closer its simplicity is to truth.
