In this blog post, we will examine how Karl Popper’s falsificationism and Thomas Kuhn’s paradigm theory—while conflicting—function complementarily to define the establishment and development of science, focusing on their philosophical implications and real-world examples.
What exactly is science? South Koreans encounter various forms of science in their daily lives, and science is a required subject in the elementary school curriculum. However, if we think about it, our ancestors lived without even knowing the word “science.” The concept of “science” was a term introduced only after Japan’s forced opening in 1876, during the process of adopting Western technology. Now, less than 150 years later, science has established itself as a core subject in the South Korean curriculum, and South Koreans live in an era where they accept science as a natural body of knowledge.
So what exactly is science that, unlike in the past, South Koreans are required to study it and have come to regard science education as a given? There is a common misconception that many people hold regarding science. People often say that the economy has developed because of science, and that various modern technological benefits—such as the internet and genetic engineering—are direct results of science. However, it is more accurate to explain these examples not as science itself, but as “technology” that has been put into practical use based on science. Of course, one cannot say that technology is unrelated to science. Nevertheless, technology is merely based on science; it is not the answer to the question of what science itself is. According to the dictionary definition, science is systematic knowledge aimed at discovering universal truths or laws.
Two philosophers of science, Popper and Kuhn, attempted to define science through their own theories. Popper advocated for “falsificationism,” also known as “critical rationalism,” while Kuhn proposed the concepts of “paradigm theory” and “normal science.” Popper was a modern British philosopher born in Vienna, Austria. During his school years, he lived through World War I, experiencing Austria’s defeat and the resulting turmoil in national and cultural pride. Amid this social upheaval, he established his philosophical stance known as falsificationism. Furthermore, after observing Einstein’s willingness to subject his own theories to rigorous testing and to abandon them if they proved false, Popper became convinced that such rigorous testing and falsification constitute the true scientific attitude. According to Popper, scientific laws or theories originate from human sensory experience, are codified through an inductive process, and are then critically falsified by new experiences and experiments, thereby becoming more refined. He argued that this process of falsification is the essence of science, and that an attitude of dogmatically clinging to a theory without subjecting it to falsification is not science.
In contrast, Kuhn explained science through the concepts of paradigms and normal science in his book ‘The Structure of Scientific Revolutions’ (1962). As mentioned earlier, while Popper viewed the dogmatic maintenance of theories as unscientific, Kuhn, on the other hand, saw the dogmatic maintenance of theories—as exemplified by the discovery of Neptune or the periodic table—as an integral part of science. While examining Aristotle’s theory of motion, Kuhn wondered, “Why are other epistemologies considered rational, yet only the theory of motion is deemed irrational?” This question led him to the concept of the paradigm. According to Kuhn, in science—just as in society—when a pioneer emerges in a specific field of research, many researchers follow in their footsteps, continuing the same tradition and advancing the field. Once such a tradition is established, subsequent researchers conduct their work based on that theory and accumulate specialized knowledge. Kuhn called this state “normal science.”
A prime example of normal science is Mendeleev’s periodic table. Mendeleev discovered periodicity by arranging elements in order of atomic weight and placing elements with similar chemical properties in the same row. During this process, he predicted the existence of an unknown element, estimated its atomic weight, and left a blank space for it on the periodic table; this was the ‘?=70’ marked next to silicon. This gap was later filled by the discovery of germanium (Ge). In this way, even when there are unexplained cases like the periodic table in normal science, maintaining existing theories and continuing research can actually lead to achievements such as the discovery of new elements.
When examining the arguments of Popper and Kuhn, it may seem that the two theories are contradictory, but in reality, I believe both positions are correct. If Mendeleev had constructed the periodic table applying only Popper’s falsificationism—and if his theory had been falsified and discarded simply because there were many blank spaces—the periodic table, which is the core of modern chemistry, would never have come into existence. In a sense, Kuhn’s framework of paradigms and normal science made the completion of the periodic table possible. Conversely, however, if we had stubbornly clung to every theory without accepting any falsification, a significant portion of the science we study today would still be filled with baseless theories, such as Aristotle’s theory of motion or Empedocles’ theory of the four elements.
Therefore, I believe that science can be most accurately explained as a combination of these two theories. To define science, we can say it is the process itself of analyzing data obtained through human senses and discovering theories inductively, the theories created through that process, and the entire series of processes involved in constructing new theories based on those existing ones. Many people try to judge the value of science based on truth and falsehood, but I believe that the issue of truth and falsehood in science—that is, whether the results are right or wrong—is a matter on a different plane from the essence of science. This is evident even in the development of atomic models. Dalton viewed the atom as a sphere that could not be further divided, but since this failed to explain cathode ray experiments, it was revised into Thomson’s model of an atom with “negative charges embedded within a positive charge.” Later, through alpha-particle scattering experiments, Rutherford proposed a model with a positively charged atomic nucleus at the center, surrounded by orbiting electrons. In modern times, the electron cloud model—which represents the position of electrons using a probability density function—has become established. From a modern perspective, the models of Dalton, Thomson, and Rutherford are all incorrect, yet we do not dismiss their theories as unscientific. Whether the results are true or false, these theories are recognized as scientific because they were constructed according to scientific procedures; indeed, the entire process of refining theories through falsification is what constitutes science.
South Korean citizens studying advanced scientific theories today can understand that they can accumulate more accurate knowledge through falsification, which clearly demonstrates the importance of falsificationism. However, at the same time, I would like to emphasize the importance of maintaining paradigms through the example of Neptune. Newtonian mechanics applies to the orbital paths of the planets in the solar system, yet Uranus’s orbit exhibited movements that did not align with Newton’s theory. According to Popper’s falsificationism, such inconsistencies serve as grounds for revising a theory. However, Newton’s theory was not wrong, nor did it actually need to be revised. The reason was that the gravitational pull of Neptune—whose existence was unknown at the time—was causing a slight wobble in Uranus’s orbit. Neptune was discovered through the efforts of scientists who sought to investigate the cause while maintaining Newtonian mechanics. Since Popper’s era came after the discovery of Neptune, he was certainly not unaware of this case. Nevertheless, from the perspective of Popper’s falsificationism, the actions of scientists at that time did not conform to a scientific attitude. However, that “unscientific behavior” became a prime example of how science actually expanded its own boundaries.
When one reflects deeply on the essence of science in this way, one begins to wonder how we can define the “science” that South Koreans learn today. I found the answer to that question while reading ‘Jang Ha-seok’s Science Meets Philosophy’, and in that process, the arguments of both Popper and Kuhn played significant roles. At first glance, falsificationism and normal science within a paradigm seem incompatible. Falsificationism requires immediate revision of a theory upon the emergence of counterexamples, whereas normal science within a paradigm maintains the theory even in the face of counterexamples while exploring the reasons behind them—a stance that may seem forced. However, as seen in the development of atomic models, falsificationism and normal science are in fact compatible. While maintaining the grand paradigm of the atom, science has evolved by accepting falsifications through experiments such as cathode ray experiments, alpha particle scattering experiments, and line spectrum analysis.
Through this process, I have come to redefine science. Science encompasses not only the theories humans construct inductively based on sensory data, but also the entire process of maintaining those theories and refining them through falsification and revision to make them more detailed and sophisticated—it includes all of that.
