Focusing on the debate between Bohr and Einstein at the Solvay Conference in 1927, this course analyzes Popper’s and Kuhn’s philosophies of science and sheds new light on the distinction between narrow and broad scientific activity.
In 1927, the Fifth Solvay Conference, held in the Belgian capital of Brussels, took place over several days in a debate that would go down in physics history. Einstein, one of the greatest minds of all time, and Niels Bohr, the foremost authority on quantum mechanics at the time, and their like-minded Copenhagen School colleagues, engaged in an elaborate debate over the question: Is quantum mechanics valid? Einstein demonstrated the incompleteness of Heisenberg’s uncertainty principle, one of the most important principles of quantum mechanics, through thought experiments, but Bohr countered by pointing out the errors in Einstein’s thought experiments. In the process, scientists were able to deepen their understanding of quantum mechanics, and the field evolved significantly to become the mature science it is today.
In controversies throughout the history of science, such as this one, scientists are dogmatic in defense of their theories within their own school of thought, but in interdisciplinary controversies, they are critical of the logic of the other side that contradicts their theories. This suggests that the nature of ‘science as practiced by an individual or a small community of scientists’ (in this case, the Copenhagen School/Einstein himself) and ‘science as practiced by a community of scientists’ (in this case, a debate between two schools) are very different. In other words, just as individual behavior and society have different properties, the practice of science has different properties depending on the collective scope of the actors and must be understood in different contexts. However, the philosophical discussions of science that have been presented so far do not make this distinction and are insufficiently inclusive of both sciences. In this paper, we will briefly introduce the philosophies of science of Popper and Kuhn, two pillars of contemporary philosophy of science, and analyze and criticize what they explain and what they are incomplete in terms of scientific debate. I will also propose a new philosophical perspective on science that analyzes science within an individual/school (hereinafter referred to as “narrow science”) and science across schools/society of scientists (hereinafter referred to as “broad science”) and provide evidence for it.
Popper’s process of scientific development can be summarized in one word: conjecture and refutation. No matter how well a theory explains many experimental results, there is no guarantee that it will also explain future observations. On the other hand, a single observation that disproves a theory is enough to reject it. Popper tried to explain scientific phenomena with a model of conjecture and refutation. First, scientists ‘speculate’ on a hypothesis to explain a phenomenon, which leads to multiple hypotheses. Scientific experiments and observations are conducted to “disprove” the hypotheses, and the disproved theories disappear. The surviving theories are accepted, but only provisionally, because they have not yet been disproved. He saw this disproving as a distinguishing feature of science, citing Eddington’s experiments and Einstein’s relativity as examples. From a disprovationalist perspective, Eddington’s experiments on the properties of light, which Newtonian mechanics and Einsteinian relativity predicted differently, resulted in Newtonian mechanics being disproved and relativity surviving attempts to disprove it.
Popper’s theory explains the debates between schools of thought, such as the Copenhagen School’s theory surviving Einstein’s attempts to disprove it at the Solvay Conference, or relativity surviving Eddington’s attempts to disprove it in the debate between Newtonian mechanics and relativity. But what about science within schools of thought? Consider the previous example in smaller categories. When Einstein presented the results of his thought experiment, the Copenhagen School didn’t look for errors in the theory of quantum mechanics, they looked for errors in Einstein’s experiment. Einstein himself adhered to his deterministic view of science and tried to find errors in quantum mechanics that contradicted it. This “dogmatic attitude” is not interpretable from Popper’s perspective.
Kuhn’s model of science, on the other hand, can be summarized as “normal science and paradigms”. A paradigm is a set of scientific norms and the traditions in science that result from those norms. Within the framework of such a paradigm, the activity of discovering new things through the thought process characteristic of the paradigm is called normal science. He likens normal science to solving a puzzle. A puzzle is a process of solving 1) a specific problem and 2) according to specific rules, and a paradigm is what defines what normal science focuses on and 2) how to study it. In this way, normal science fits natural phenomena into a paradigm. However, as the number of phenomena that cannot be interpreted by paradigms accumulates, a new paradigm is proposed to solve them. Kuhn argued for a “monopolistic paradigm” in which a struggle between the new and old paradigms occurs, leading to a consensus paradigm in the scientific community, and only the winning paradigm remains in normal science.
Kuhn’s theory explains the attitudes of scientists in intra-disciplinary science, which cannot be interpreted in terms of Popper’s perspective described above. The Copenhagen School’s search for errors and interpretation of the results of Einstein’s thought experiments to fit their paradigm, and Einstein’s attempt to interpret Heisenberg’s uncertainty principle in terms of his own paradigm, can both be interpreted through Kuhn’s arguments. However, in a broader sense, it does not explain science as a society of scientists. Einstein’s deterministic paradigm was defeated by the quantum mechanics paradigm of the Copenhagen School. However, we still see deterministic paradigms such as statistical mechanics being applied to sufficiently statistical systems, and science being used to predict future phenomena, so we are far from seeing a monopoly of paradigms or the disappearance of defeated paradigms.
We have seen the scope of Popper’s and Kuhn’s theories and their limitations. We now propose the following complementary model from the Popperian, Kuhnian, and pluralist perspectives that can go beyond these limits. First, science in the narrow sense can be interpreted in terms of paradigms. In his Critique of Pure Reason, the philosopher Kant scrutinized the human cognitive system. He said that when a person accepts an event or phenomenon, he or she does not accept it purely as an event or phenomenon in itself, but “human perception creates a concept of the object” (Copernican transition). This can be explained through the relationship between phenomena, categories, and schemas in his model of perception. We receive sensations through our sensory organs, analyze them, and view the real world as a phenomenon. Phenomena are processed and categorized through categories, which are a priori human classification systems, and schemas are the link between empirical ‘phenomena’ and categories. For example, a person perceives the phenomenon of a mosquito bite as a swollen bite through their senses. Originally, the mosquito bite and the swelling of the skin are completely independent phenomena, but through schemas, the person puts them into the category of “cause and effect” and eventually perceives that mosquito bites cause swelling. In other words, schemas play an important role in connecting experience and perception, and these schemas are called schemata because they are organically connected and ultimately organize the way we organize our cognition.
Kant viewed schemata as a priori, but this claim was later modified by psychologist and philosopher Jean Piaget’s theory of cognitive development. He explained the relationship between schema and cognition in terms of assimilation and accommodation. Assimilation refers to the process of reorganizing and integrating new information into one’s schema, similar to Kant’s epistemology, when a person takes in new information. Accommodation, on the other hand, is the process by which a person’s existing schema is changed or a new schema is created as a result of experience. For example, an adult with more experience than a baby often experiences the same phenomenon and perceives it at a higher level. From the perspective of conditioning, people with different upbringings have different schemas, and from the perspective of assimilation, different schemas mean that they end up perceiving the same phenomenon differently.
Now let’s look at science in the narrow sense from a schema perspective. There are many similarities between schemata and paradigms. For example, consider the process of reading. From the perspective of schema theory, reading is the process by which a reader reconstructs the meaning of a text presented by an author, and the reader’s schema determines 1) what parts of the book to focus on and 2) how to take in (perceive) the meaning. The process by which individuals build knowledge, i.e., bring in new knowledge based on their schemas, is very similar to the scientific process in Kuhn’s normal science. In normal science, paradigms dictate how phenomena are viewed and how problems are solved by science, which is similar to how individuals use schemas to determine how they take in phenomena and what elements they are interested in and focus on. This can be interpreted as the epistemological process of accepting knowledge is itself a form of building on existing structures in the first place. In other words, since the process of building scientific knowledge is itself based on schemas, the scientific process is bound to be based on what Kuhn called “paradigms”.
This can also be extended to apply to science practiced by small groups of scientists, called disciplines. People in the same school have similar ways of looking at phenomena and similar interests. Belonging to the same discipline means having similar schemata, which in turn can be extended to groups that share the same paradigm. In other words, science done by individuals or in the same discipline (groups that share the same schema) can be explained through Kuhn’s paradigm and normal science. This is consistent with the stance taken by the Copenhagen School in the Bohr-Einstein debate presented in the introduction and explains the phenomenon that many scientific schools have different perspectives and try to solve different problems.
On the other hand, the interpretation of “science in the broad sense” that occurs between schools of thought and in the society of scientists as a whole is not as simple as Kuhn’s claim that paradigms are the result of a competition among several paradigms during a scientific revolution, with the winning paradigm surviving and the losing paradigm disappearing. A classic example is Newtonian mechanics. Although Newtonian mechanics was defeated in the scientific revolution by relativity and quantum mechanics in the early 20th century, it is still alive and well because it is a paradigm that works very well in the everyday range of velocities and masses. This is inconsistent with Kuhn’s philosophy, which, as we have seen, insisted on an exclusive paradigm.
We can observe that in a society of scientists, multiple paradigms coexist, rather than a single paradigm that ultimately triumphs in the Scientific Revolution, as Kuhn claimed. In some cases, different paradigms may approach a phenomenon simultaneously, which leads to a conflict between paradigms and a process of mutual criticism between schools of thought. This is similar to Popper’s process of conjecture and refutation, where scholars from different paradigms come up with theories in the form of multiple hypotheses, and scientific discussion takes place through mutual criticism at the point of conflict. However, the difference with Popperian disprovism is that in many cases, there is not much overlap between the paradigms of different schools of thought, so the entire paradigm is not abandoned because of a small part that is disproved. For example, Newtonian mechanics and relativity are different, and the problems they seek to solve are different, so when a theory is disproved, the paradigm shifts in a way that reduces the scope of the theory’s application rather than eliminating the paradigm itself. This means that the theories in each paradigm are complementary to each other, which leads to pluralism.
So why is there a difference between narrow and broad science? It is because of the different schemata that people have organized in their lives. The schemata we are talking about here are not just scientific knowledge, but also worldviews and philosophies of science, which are ways of looking at the world. Structuralist theories argue that human attributes are not inherent in us, but are determined by our relationships with the world around us, and they seek to explain language, humanity, culture, politics, and economics by identifying the structure of these relationships. Structuralism implies that schemata, the knowledge structures embedded in the human brain, are also subject to many individual differences through our relationships with the surrounding society. In other words, in a society of scientists, there are people with different schemata, and people with the same schemata gather to form ‘schools’ that share the same paradigm and interact with other schools with different paradigms. In this process, science in the narrow sense, practiced within schools of thought with the same schemata, attempts to interpret phenomena and define problems according to their schemata, or paradigms, resulting in a scientific process similar to Kuhn’s argument. On the other hand, science in the broad sense is an exchange between people who do not share the same schema, so they take a mutually critical stance, which can be expressed as a compromise between Popper’s antipodeanism and pluralism. In other words, the reason why Kuhn’s and Popper’s philosophical views of science do not fully describe scientific phenomena is that they do not set the scope of shared schema and do not distinguish between individual science and society’s science. This limitation can be addressed by categorizing scientific behavior into narrow and broad science.
Let’s look at the Bohr-Einstein debate in this new light. Einstein grew up learning the deterministic second law of thermodynamics (the law of increasing entropy) and was inclined to predict phenomena through perfect physical laws. This led to his deterministic worldview (schemata), and he was a scholar of the relativistic paradigm, which is based on the premise that information transfer cannot occur at speeds beyond the speed of light. Bohr, on the other hand, had been involved in quantum mechanics, being the first to propose a quantum model of the atom. This leads to a paradigm (schema) called quantum mechanics. In quantum mechanics, the phenomenon of quantum entanglement is known as “nonlocality,” and it seemed as if it was a phenomenon of information traveling faster than the speed of light, which scholars at the time thought was contrary to relativity. (It has now been proven that no meaningful information travels faster than the speed of light.) The Bohr-Einstein debate is a scientific activity in the broadest sense of the word. The Bohr-Einstein debate is a scientific activity in the broadest sense of the word, as two schools of thought from different paradigms are sharply divided and criticizing the intersection of schemata (a concept that encompasses both the deterministic worldview and the relativistic/quantum paradigm). On the other hand, if we go inside the Bohr-Einstein debate and look at “scientific activity in the narrow sense,” we can see that the schools that share the same schema are engaged in what Kuhn called “puzzle solving” to defend their paradigms.
Scientific societies, like societies in general, need to distinguish between the behavior of parts and the behavior of the whole, and in this case, scientific activity is better interpreted. We first analyze science in the narrow sense of occurring within an individual or small group of scientists, a school of thought, using the similarity in structure between schema theory and Kuhn’s paradigm of normal science. Then, the broader scientific activity that takes place between groups of scientists (schools) and within the society of scientists that encompasses them was analyzed using Popper’s process of speculation and dispute and pluralism. Finally, the difference between the two is explained from a structuralist perspective as the different schemata of human beings depending on the environment in which they are raised, which leads to differences in the construction of paradigms to interpret phenomena and define problems, and the scientific event of the Bohr-Einstein debate is analyzed from this perspective.
Kuhn’s paradigm is suitable for explaining normal science and paradigms that occur within a discipline, but it is insufficient to explain the current scientific system where multiple paradigms coexist in terms of mutual criticism and pluralism between disciplines, such as the Bohr-Einstein debate. On the other hand, Popper’s conjectures and arguments were well suited to explain attempts to disprove paradigms in scientific activities in a broad sense, but they were inaccurate in explaining normal scientific activities within disciplines. Therefore, if we consider science as a part and a whole by dividing the scope of the group of actors who do science, we can look at modern science in a more rigorous and new light by compromising the arguments of two great philosophers of science and a pluralistic perspective.
