In this blog post, we will look at how Popper’s theory of counter-proof and Kuhn’s theory of paradigm can coexist in the progress of science.
The development of science began around the 16th and 17th centuries when scientists such as Galileo, Kepler, and Newton compiled classical physics, and in the 19th century, Einstein, Bohr, and Schrödinger created a new discipline called quantum mechanics, which greatly changed people’s perception of the world. On the other hand, looking at the history of science from a philosophical perspective leads to fundamental questions about where and how science is going. Does science have any truth? How does science progress? How did past theories fail or succeed to become the science of today? By answering these questions, we can consider the direction in which science should go in the future. Many philosophers of science have put forward their own theories on this, and Karl Popper’s “Falsificationism” and Thomas Kuhn’s “Paradigms in Science” are two representative theories that stand in opposition to each other. In this essay, I will briefly introduce Popper and Kuhn’s theories of falsificationism and paradigms, and then, from the perspective of scientific progress, Popper’s ” After describing how Kuhn’s “paradigm” is correct and incorrect in some ways, focusing on “falsificationism,” I will show through examples that the two theories of Popper and Kuhn are concepts that coexist by subordinating the paradigm to falsificationism.
First of all, in order to define scientific progress, it is necessary to distinguish between science and non-science, or pseudoscience. Popper presented a clear criterion for this, which is “criticability.” In other words, if a hypothesis or theory has a structure that cannot be logically criticized, it is pseudoscience. The hypothesis that “God exists” cannot be disproved by any means, so it cannot be called science. On the other hand, the hypothesis that “the gravity of the Earth is uniform at any point on the Earth” can be disproved by measuring the gravity at two points on the Earth with a large difference in altitude, which can be said to be “scientific” from Popper’s point of view. As such, “scientific” as defined by Popper does not distinguish between true and false, but rather means “having meaning.” In addition, for these hypotheses to be valuable, they must have the purpose of solving practical problems of the time, and philosophical and scientific propositions without this purpose are nothing more than meaningless nonsense. A meaningful and testable hypothesis is subjected to a test to try to disprove it, and if it is proven to be false, the hypothesis is discarded. Since these speculations cannot be proven to be entirely true, Popper defines that a speculation that has not been proven to be false through multiple tests is highly reliable, and by repeating this process of testing meaningful speculations and disproving them, science approaches the truth, which is the essence of all things, and this is called scientific progress.
If we summarize Popper’s argument about “falsificationism,” science develops in a cumulative manner through a process of repeated speculation and falsification. In response, Thomas Kuhn introduced the concept of “paradigm” to science and developed a theory that contrasts with Popper’s argument. The paradigm defined by Kuhn is somewhat ambiguous in its meaning and scope, but broadly speaking, it refers to the overall characteristics of the science that defined the era. For example, the ‘heliocentric theory’, which was accepted as truth before Galileo, can be seen as a paradigm. Just as the heliocentric theory is not accepted today because evidence has been found that proves the geocentric theory, paradigms are relative concepts formed by the beliefs of people at the time and are not absolute. When there are many problems that cannot be explained by the existing paradigm, a new paradigm is established. Kuhn defined this establishment of a paradigm as a “scientific revolution,” and this is the most conflicting part of Kuhn and Popper’s arguments. Kuhn argues that scientific knowledge is gradually accumulated through repeated attempts to make better predictions by disproving previous predictions and existing predictions, and that this is the path to scientific truth. In contrast to Popper, who argued that this scientific revolution is the destruction of the achievements built up in the existing paradigm and the establishment of a new paradigm. In addition, the new paradigm can solve more problems than the existing paradigm, so although they did not deny that the scientific revolution is directly linked to the progress of science, they denied that such progress in science leads to any truth. This is because the paradigm shift is not about continuing to move in one direction, but about finding a better new direction.
However, I argue that Popper’s counter-evidence and Kuhn’s paradigm should exist in a coexisting structure, not in a structure in which they are in opposition to each other. To make this argument, which contrasts the theories of the two scholars, more convincing, I will first explain the paradigm and the phenomena caused by it based on the theory of refutationalism. The biggest difference between Kuhn’s paradigm and Popper’s refutationalism is the accumulation of knowledge. A paradigm shift means the collapse of the knowledge accumulated in the existing paradigm. In addition, Kuhn’s paradigm theory presents the Kuhn-loss problem, which is that a new paradigm may not be able to explain what a previous paradigm could. These problems arise from the fact that the concept of scientific progress is defined incorrectly. In the end, a new paradigm originates from research based on an existing paradigm, so even if a paradigm shift occurs as a result of a scientific revolution, it is difficult to accept the claim that the new paradigm destroys the existing paradigm. Let’s think about it based on the “duality of light,” which is the beginning of quantum physics. Previously, light was only considered as a wave, but problems arose that could not be explained by the wave nature of light alone, such as the photoelectric effect (a phenomenon in which electrons are emitted from a metal plate only when light of a certain frequency or higher is shone on the plate, regardless of the intensity of the light). A hypothesis emerged that light is an uncertain entity that is sometimes a wave and sometimes a particle, and light was in crisis of the existing paradigm that it is a pure wave. Later, it was revealed that light is an entity that has both the properties of a wave and a substance, and this became the new paradigm. However, even after the scientific revolution, research based on the particle nature of light has shattered the existing paradigm that light is a pure wave, but there are many cases where the particle nature of light does not need to be considered, so light is often treated simply as a wave, and research on the characteristics of electromagnetic waves before the paradigm shift is still valid. This is the case when a new paradigm has taken hold, but the knowledge of the existing paradigm remains intact without being completely destroyed. In other words, the scientific revolution does not establish a completely new paradigm after the collapse of the existing paradigm, but rather achieves scientific progress by improving the existing paradigm, and the degree of improvement varies depending on how much the existing paradigm collapses. For example, when a problem is found on the fifth floor of a tower that has been built up to the tenth floor, the tower is not completely demolished and rebuilt, but the problematic part and the parts associated with it, that is, the floors after the fifth floor, are demolished and rebuilt.
Let’s interpret the example of light in accordance with Popper’s theory of falsification. The existing paradigm of optics can be seen as a collection of various hypotheses and theories that have accumulated reliability by successfully passing many tests of falsification, and the theory that light is a wave is one of them. The photoelectric effect is a successful refutation of the theory that light is a wave, and through this, the hypothesis that light is both a wave and a particle has been tested and remains to this day as a theory that light is composed of photons that have both the properties of waves and particles. A paradigm shift is not about a paradigm that is completely different from the existing one, but about modifying the perception of existing people through refutation, and this can be said to be the progress of science.
In the case of the Kun-Ross problem, it is caused by hasty decisions about the scientific revolution and by limiting scientific progress to explaining more things right away. Let’s consider the two cases where a new paradigm cannot explain what was previously explainable. The first case is when the new paradigm has not yet been fully established. A typical example is the paradigm shift in astronomy, from geocentrism to heliocentrism. Let’s look at this through Kuhn’s paradigm theory. Geocentrism was able to explain various astronomical phenomena in measurements and calculations based on the data observed at the time without contradiction. However, as time passed and celestial phenomena that could not be explained by the geocentric theory, such as the changing phases of Venus, were observed, people like Galileo and Copernicus began to doubt the geocentric theory, and a new paradigm called the heliocentric theory emerged around them. However, the early heliocentric theory was much more complicated and lacked evidence and persuasiveness in its calculations of celestial motion compared to the widely accepted geocentric theory at the time. In addition, Tycho Brahe’s corrected heliocentric theory more accurately explained the errors of the geocentric theory that he tried to correct. The heliocentric theory was accepted as the official theory after the accuracy of the heliocentric theory was proven through the theories of scientists such as Kepler and Newton (Kepler’s laws, the law of universal gravitation, etc.). As a result, the paradigm shifted from geocentrism to heliocentrism, but before heliocentrism was fully established, the Copernican heliocentrism that he advocated caused the Koon-Ross problem. This is because the new paradigm, heliocentrism, was less convincing than geocentrism. Let’s reinterpret this based on the principle of counterproof. When Copernicus was advocating heliocentrism, geocentrism was still the dominant theory, and at this time, heliocentrism was not yet a new “paradigm” and could be seen as a hypothesis that attempted to point out the contradictions of geocentrism. This hypothesis was disproved by the heliocentric theory of Tycho Brahe, which was in contrast to the existing geocentric theory and proved to be cumbersome, and it failed the scientific revolution. Later, the more systematic heliocentric theory emerged as a hypothesis again due to the development of physics, and it successfully disproved the geocentric theory by explaining everything that the geocentric theory explained without any problems and resolving the contradictions of the geocentric theory. It can be said that the heliocentric theory was established as a new paradigm. If a new hypothesis can explain a phenomenon that can be explained (and can be verified in real life) within the existing paradigm, then this is not a case of the post-scientific revolution reducing the realm of explainability, but an attempt to do so. If this hypothesis gains persuasiveness and can disprove and surpass the existing hypothesis, a paradigm shift will occur. On the contrary, if the new hypothesis does not gain persuasiveness, a scientific revolution will not occur and the existing paradigm will be maintained.
The second case is when the paradigm established through the first case fails to explain what the existing paradigm could explain. When quantum mechanics was not developed and Newtonian mechanics was all there was in mechanics, it was believed that no matter how small an object was, any movement could be accurately predicted if the physical quantities of the object were sufficiently understood, and this was no exception for the movement of atoms. However, as research into the microscopic world (the small world invisible to the eye) continued, the principle of uncertainty was accepted as a result of quantum mechanics overturning the paradigm of classical mechanics. This means that the movement of particles that could be explained by classical mechanics could no longer be explained by the newly established quantum mechanics. However, in quantum mechanics, this “inexplicability” is the very essence of scientific progress and a new paradigm.
Kuhn also proposed the “impossibility of commutation,” which states that there is no common measure between different paradigms. As an example, the Pythagorean school’s paradigm, which states that all things are made up of a ratio of rational numbers, was later established as a new paradigm for numbers by revealing that the ratio of the hypotenuse to the other sides of an isosceles right triangle cannot be expressed as a rational number, and the impossibility of a common measure for the hypotenuse and the other sides of the triangle is established. Kuhn argues that the impossibility of a commitment makes it impossible to compare the two paradigms, but if the scientific revolution is seen as an improvement of the paradigm, then the impossibility of a commitment becomes unnecessary. If there is an area where the existing paradigm and the new paradigm cannot be reconciled, that area is the area where the problem is found and discarded as a refutation in the existing paradigm, and new hypotheses and theories are established, which are distinguished from the knowledge derived from the existing paradigm. Now that we have found that the ratio of the hypotenuse to the other sides of an isosceles right triangle cannot be expressed as a rational number, there is no need to compare it with the Pythagorean school’s theory, which previously tried to express it as a rational number, and there is no need to discard the Pythagorean school’s theories on right triangles, which were previously explained as rational numbers. Knowledge that could be explained well with the existing paradigm does not need to be overturned, so the part that cannot be proven is the knowledge that was overturned in the process of the scientific revolution, and it is unnecessary to compare it with a new paradigm that is more reliable after it has withstood the test of refutation.
In conclusion, from the perspective of counter-proof theory, if we interpret the paradigm of an era as a set of hypotheses and theories that can be disproved, the scientific revolution can be seen as the emergence of an improved paradigm accompanied by new theories and hypotheses that explain the contradictions discovered by disproving the existing paradigm, and through this, the scientific revolution has shown that scientific progress can be made without having to consider the impossibility of commitments between paradigms. This makes it possible to clarify the relationship between scientific progress and scientific truth. Truth is the essence of all things, and there is no way for humans to know for sure whether this essence exists or whether they have reached it. However, as the existing paradigm is disproved and the new paradigm that has been improved upon by this can explain more than before and describe more about the world, it can be said that science is moving towards the truth.
