The Bohr-Einstein debate distinguishes between narrow (within a school of thought) and broad (across schools of thought) science in the philosophy of science, and is analyzed using the theories of Popper and Kuhn.
In 1927, at the Fifth Solvay Conference on Physics in Brussels, Belgium, a debate took place over several days that has gone down in the history of physics. Einstein, who was considered the greatest intellect of mankind, Niels Bohr, the greatest authority on quantum mechanics of his time, and the Copenhagen School, who shared his views, engaged in a sophisticated debate on the topic “Is quantum mechanics valid? Einstein pointed out the imperfection of Heisenberg’s Uncertainty Principle, one of the important principles of quantum mechanics, through a thought experiment, but Bohr pointed out and refuted the errors that occurred in Einstein’s thought experiment. In the process, scientists were able to gain a deeper understanding of quantum mechanics, which has since evolved significantly and taken the form of a well-established discipline.
Looking at the various debates in the history of science, such as this one, scientists take a dogmatic stance to defend their theories within their own school of thought, but take a critical stance to break down the logic of the opposing side in a debate between schools of thought. This suggests that the nature of “science conducted by individuals or small groups of scientists in society” (in this case, the Copenhagen School/Einstein as an individual) and “science from the perspective of a school or the entire scientific community that encompasses it” (in this case, the debate between the two schools) are very different. In other words, just as individual behavior and society have different properties, the act of science has different properties depending on the scope of the group of actors and must be understood in different contexts. However, the scientific and philosophical discussions presented so far have not distinguished between them and are insufficient to encompass both sciences with different natures. Therefore, I will briefly introduce the scientific philosophies of Popper and Kuhn, which are the two pillars of modern philosophy of science, and analyze and criticize what these theories explain from the perspective of scientific debate and where they are incomplete. In addition, I propose and provide evidence for a new scientific and philosophical perspective that divides science within an individual/school of thought (hereafter referred to as “narrow science”) and science between schools of thought/the entire scientific community (hereafter referred to as “broad science”).
In a nutshell, Popper’s view of scientific progress is “speculation and refutation”. No matter how well a theory explains many experimental results, there is no guarantee that it will explain future observations. On the other hand, even a single observation that disproves the theory will negate it. Therefore, Popper tried to explain scientific phenomena using the model of conjecture and refutation. First, scientists formulate hypotheses to explain phenomena, and then they postulate various hypotheses. Various scientific experiments and observations are conducted to “disprove” the proposed hypotheses, and the disproved theories disappear. On the other hand, the surviving theories are accepted because they have not yet been disproved, but only provisionally. He saw these refutations as a distinguishing feature of science, citing Eddington’s experiments and Einstein’s theory of relativity as representative examples. From the perspective of the theory of refutations, Eddington conducted an experiment on the properties of light that were predicted differently by Newtonian mechanics and Einstein’s theory of relativity. The result can be interpreted as disproving Newtonian mechanics, while relativity survived the attempt to disprove it.
At the Solvay conference, Popper’s theory explains well the debate between schools of thought, such as the Copenhagen school’s theory surviving Einstein’s attempt to disprove it, or relativity surviving Eddington’s attempt to disprove it in the conflict between Newtonian mechanics and relativity. On the other hand, what about science within a school of thought? Let’s consider the previous example in a smaller category. When Einstein presented the results of his thought experiment, the Copenhagen school of thought did not find fault with the theory of quantum mechanics, but rather with the errors that occurred in Einstein’s experiment. Einstein, too, held to his earlier deterministic view of science and found fault with the errors in quantum mechanics that contradicted it. This “dogmatic attitude” cannot be interpreted from Popper’s point of view. On the other hand, the model of science presented by Kuhn can be summarized as “normal science and paradigm”. A paradigm is a word that refers to a kind of scientific norm and the tradition in science that has been created by this norm. Within this paradigm, activities that reveal new things through the paradigm’s unique thought process are called normal science. He compared normal science to solving a puzzle. A puzzle is a process of solving a specific problem according to specific rules, and this is because the paradigm determines what to focus on and how to study normal science. As such, normal science is the work of fitting natural phenomena into a paradigm. However, as phenomena that cannot be interpreted with a paradigm accumulate, a new paradigm is proposed to solve them when they reach a certain level. Kuhn argued that in this process there is a struggle between the new and old paradigms, and the paradigm that is agreed upon by the scientific community is adopted, and only the paradigm that ultimately wins in normal science remains as the “monopolistic paradigm. Kuhn’s theory explains the attitudes of scientists within a school of thought that could not be interpreted from the Popperian perspective described above. Kuhn’s argument can be applied both to the Copenhagen School’s process of finding and interpreting errors to fit their paradigm with the results of Einstein’s thought experiment, and to Einstein’s attempt to interpret Heisenberg’s uncertainty principle with his own paradigm. However, it is difficult to explain science in the entire scientific community from a broader perspective. Einstein’s deterministic paradigm was defeated by the quantum mechanical paradigm of the Copenhagen School. However, even now, research is being conducted in which deterministic paradigms such as statistical mechanics are applied to sufficiently statistical systems, and when we look at attempts to predict future phenomena using science, we are far from the disappearance of exclusive paradigms or paradigms that have lost the battle.
We have already examined the scope and limitations of Popper’s and Kuhn’s theories. We propose the following complementary model from the perspective of Popper, Kuhn, and pluralism that can overcome these limitations. First, science in the narrow sense can be interpreted from the perspective of paradigms. The philosopher Kant analyzed the human cognitive system in detail in his Critique of Pure Reason. He said that when a person accepts an event or phenomenon, he or she does not accept it as it is, but rather “human perception creates the concept of the object” (the Copernican Revolution). This can be explained by the relationship between phenomena, categories, and schemata in the cognitive model he proposed. People receive sensations through their sensory organs, analyze them, and view the real world as a single phenomenon. A phenomenon is processed and classified by categories, which are a classification system that people have a priori. A schema is what connects the empirical “phenomenon” to the categories. For example, let’s say a person has experienced a phenomenon in which a mosquito bite causes the bitten area to swell. Originally, the mosquito bite and the swelling of the skin are completely independent phenomena, but the person, through a schema, places this phenomenon in the category of “cause and effect” and eventually comes to realize that the mosquito bite causes the swelling. In other words, schemata play an important role in linking experience and perception, and these schemata are organically connected to ultimately shape the way people construct knowledge.
Kant viewed schemata as a priori, but this claim was later modified by the cognitive developmental theory of psychologist and philosopher Jean Piaget. He explained the relationship between schemata and cognition in terms of assimilation and accommodation. Assimilation refers to a process similar to Kant’s epistemology in which a person accepts new information and reorganizes and integrates it into his or her schemata. On the other hand, accommodation refers to the process of changing an existing schema that a person already has through experience, or creating a new schema. An example of this is when an adult with more experience than a baby has a higher level of awareness even though they are experiencing the same phenomenon. From the perspective of adaptation, people raised in different environments have different schemas, and from the perspective of assimilation, different schemas mean different perceptions of the same phenomenon.
Now let’s look at science in the narrow sense from the perspective of schema. Schemas and paradigms have a lot in common. Consider, for example, the process of reading. From the perspective of schema theory, reading is a process in which the reader reconstructs the meaning of the text presented by the author, and the reader’s schema determines 1) what parts of the book to focus on and 2) how to interpret (recognize) the meaning. The process by which individuals accumulate knowledge, that is, the process of acquiring new knowledge based on schemas, is very similar to the scientific process that occurs in normal science, as Kuhn argued. In normal science, a paradigm determines how to view a particular phenomenon and how to solve a particular problem using a particular type of science. This is similar to the process by which an individual decides how to accept a phenomenon through a schema and decides which elements to focus on and pay attention to. This can be interpreted as the epistemological process of an individual’s acceptance of knowledge itself occurring in the form of building something on top of existing structures. In other words, the process by which an individual builds scientific knowledge is based on schemas, so the scientific process must be based on the system of “paradigms” that Kuhn spoke of.
If we extend this, it can be applied to science done by a small group of scientists, a school of thought. People in the same school of thought have similar perspectives on phenomena and are interested in similar areas. Belonging to the same school of thought means that the schemas are similar, which can be extended to mean a group that shares the same paradigm. In other words, the science of an individual or a school of thought (a group of people who share the same schema) can be explained by Kuhn’s paradigm and normal science. This is consistent with the attitude of the Copenhagen School in the Bohr-Einstein debate presented in the introduction, and it can explain the phenomenon of many scientific schools trying to solve different problems with different perspectives.
On the other hand, let’s interpret “science in the broad sense” as occurring between schools of thought and in the scientific community as a whole. In the actual scientific community, paradigms are not explained as simply as in Kuhn’s argument, where only the remaining paradigm survives after winning the competition among several paradigms in the process of scientific revolution, and the defeated paradigm disappears. Newtonian mechanics is a typical example. Although Newtonian mechanics was defeated by relativity and quantum mechanics in the scientific revolution of the early 20th century, it has survived to this day because it is a paradigm that works very well in the everyday range of speeds and masses. This does not fit with Kuhn’s philosophy of claiming an exclusive paradigm, as was raised earlier.
This allows us to observe that in the scientific community there is not just one paradigm that ultimately won the scientific revolution, as Kuhn claims, but rather multiple paradigms coexisting. At this point, there may be cases where different paradigms approach a single phenomenon at the same time, in which case a conflict between the paradigms occurs, resulting in a process of mutual criticism between schools of thought. This is similar to Popper’s process of speculation and refutation, in which scholars with different paradigms propose theories in the form of different hypotheses, and scientific discussions are conducted through mutual criticism at the points of conflict. However, the difference with Popperian falsificationism is that in many cases the paradigms of the schools of thought do not have much mutual contact, so they do not abandon the entire paradigm because of a small part that has been disproved. For example, the main content of Newtonian mechanics is different from the main content of relativity, and the problems to be solved are also different. Therefore, when a theory is disproved, the paradigm itself disappears, but the range in which the theory can be applied is reduced, and the paradigm changes in that direction. This means that the theories in each paradigm complement each other, leading to pluralism.
Then why does the difference between the narrow and broad sense of science occur as described above? It is because the schemata that people have built up throughout their lives are all different. The schemata we will discuss here are concepts that include not only simple scientific knowledge, but also worldviews and scientific philosophies, which are all perspectives on the world. The structuralist theory argues that human characteristics are not inherent, but are determined by relationships with the surrounding society. In other words, it is a theory that attempts to explain language, humanity, culture, politics, and economics by identifying the structures that these relationships form. A closer look at structuralism suggests that schemata, the knowledge structures inherent in the human brain, can also become more individualistic through relationships with the surrounding society. If we look closely at the assimilation and accommodation processes of Jean Piaget, the structuralist epistemologist mentioned earlier, we can see that the cognitive system changes according to the individual’s experience. In other words, there are people with different schemata in the scientific community, and people with the same schemata form a “school” that shares the same paradigm and interacts with other schools with different paradigms. In this process, the scientific process occurs in a format similar to Kuhn’s argument, because the narrow sense of science, conducted within a school of thought with the same schema, tries to interpret phenomena according to its schema or paradigm and define problems. On the other hand, science conducted in the broad sense is an exchange between people who do not share the same schema, so it takes a critical stance, which can be expressed as a compromise between Popper’s positivism and pluralism. In other words, it can be interpreted that the reason why the scientific and philosophical perspectives previously presented by Kuhn and the scientific and philosophical perspectives presented by Popper were not able to fully explain scientific phenomena was because they considered science as performed by individuals and science as performed by society as the same, without defining the scope of shared schemata and without distinguishing between the two. It seems that this limitation can be overcome by classifying scientific activities into narrow and broad senses of science.
Let’s look at the Bohr-Einstein debate from this new perspective. Einstein grew up with the deterministic law of the second law of thermodynamics (the law of increasing entropy) and had a strong tendency to predict phenomena by perfect physical laws. This led to his deterministic worldview (schema), and he was a scholar of the relativity paradigm, which is based on the premise that information cannot be transmitted faster than the speed of light. On the other hand, Bohr had a lot of experience with quantum mechanics, to the extent that he was the first to propose a quantum model of the atom. This is related to the paradigm (scheme) of quantum mechanics. In quantum mechanics, the phenomenon of quantum entanglement has caused a phenomenon of “non-locality,” which appeared to be a phenomenon of information transfer faster than the speed of light, and therefore scientists at the time thought that it violated relativity. (In fact, it has since been shown that meaningful information transfer does not occur at speeds faster than the speed of light.) The Bohr-Einstein debate is a scientific activity in the broadest sense, if we look at the debate itself. This is because two schools of thought with different paradigms are sharply confronting and criticizing each other at the point of intersection of the schema (a concept that includes both a deterministic worldview and a relativistic/quantum mechanical paradigm). On the other hand, if we look at the Bohr-Einstein debate and at “scientific activities in the narrow sense,” we can see that schools of thought that share the same schema go through the “puzzle-solving” process that Kuhn argued for in order to defend their own paradigms.
As in the case of society in general, the scientific community should distinguish between the difference in behavior from the perspective of the part and the perspective of the whole, and in this case scientific activities can be better interpreted. First, the narrow sense of science that occurs within a school of thought, which is an individual or a small group of scientists, was analyzed using the similarity of the structure of schema theory and Kuhn’s normal science paradigm. Then, the broad scientific activities that take place between groups of scientists (schools) and the entire scientific community that includes them were explained by combining Popper’s process of speculation and refutation with pluralism. Finally, the author explained the reason for the difference between the two from a structuralist perspective, in which the schema varies depending on the environment in which humans grow up, resulting in differences in the paradigm configuration for interpreting phenomena and defining problems. From this perspective, the author analyzes the scientific event of the Bohr-Einstein debate.
Kuhn’s paradigm is suitable to explain normal science and paradigms that occur within a school of thought, but it is insufficient to explain the current scientific system in which multiple paradigms coexist from the perspective of mutual criticism between schools of thought and pluralism, such as the Bohr-Einstein debate. On the other hand, Popper’s speculation and refutation well explained the attempt to disprove paradigms in scientific activities in a broad sense, but on the contrary, it was wrong to explain normal scientific activities within a school of thought. Therefore, if we divide the group of scientists into a subset and the whole and think of science as a subset and the whole, we can see modern science from a more rigorous and new perspective by combining the arguments of the two great philosophers of science and their pluralistic viewpoints.
