Science has been trusted since the modern era as an indisputable truth, but in the mid-20th century, Thomas Kuhn shook this belief by arguing in The Structure of Scientific Revolutions that scientific progress is driven by cyclical revolutions. Kuhn explained that science chooses new paradigms based on irrational rather than rational factors, and this led to a shift away from blind faith in science as absolute truth and toward critical reflection.
Since the modern era, science has gained the unbounded trust of humans. The epistemological justification that science is a certain truth, along with the material abundance it promised, further strengthened our faith in it. The development of science and philosophical explanations of the nature of science are inextricably linked. However, since the mid-20th century, new philosophical accounts of the nature of science have emerged, allowing us to move away from blind trust in science and engage in critical reflection. The social, historical, and political nature of science and technology began to emerge, challenging the belief that science is definitive knowledge. Changing views of science changed civic attitudes toward science, which in turn influenced policy decisions and changed the culture at large.
One philosopher who decisively changed the way we view science in the 20th century was Thomas Samuel Kuhn (1922-1996). He challenged the prevailing consensus on the nature of science up until the mid-20th century. In The Structure of Scientific Revolutions, published in 1962, he shook the foundations of the traditional belief that science is an activity that moves toward unchanging truths. He argued that science is more like human activities like art and religion, and that historical examples show that scientific progress has been irrational. How can a supposedly rational science develop irrationally? First, let’s take a closer look at his argument, which revolutionized the way we view science.
According to Kuhn, the structure of scientific progress is organized into stages. After accepting a paradigm, a society of scientists changes as follows
1. perform normal science, solidifying the paradigm.
2. a paradigm crisis occurs as problems that cannot be solved by the existing paradigm accumulate in the process of performing normal science.
3. a new paradigm emerges that is different from the existing paradigm and enters the stage of scientific revolution, in which two or more paradigms compete.
4. When the new paradigm overtakes the old one and is accepted by the scientific community, a new phase of normal science begins.
Kuhn argued that historically, irrational factors, such as aesthetic simplicity or beauty, or the reputation or personal beliefs of scientists, have often played a role in the process of a community of scientists abandoning an old paradigm and switching to a new one. He described this as incommensurability between two paradigms. Incommensurability means that it is impossible to say which of the two paradigms is superior because the old paradigm and the new paradigm value different problems and solutions. In other words, the two paradigms cannot be compared or evaluated on the same basis. Therefore, Kuhn’s argument is that scientists’ abandonment of the old paradigm and acceptance of the new paradigm is primarily determined by the aforementioned irrational factors, not by rational criteria. In other words, paradigm shifts and scientific advances are driven by irrational factors, similar to religious conversions.
As Kuhn argues, irrational factors can play a large role in the process of individual scientists abandoning old paradigms and choosing new ones. This argument seems hard to refute because it is based on historical examples of scientific progress. However, if we look at scientific progress from a long-term perspective, where a society of scientists as a whole fully embraces a paradigm and it becomes entrenched, then I believe that scientific progress is driven by rationality rather than irrationality. Before discussing this, let’s look at the process of how geodynamics came to be accepted as a new paradigm by the scientific community.
We know from common knowledge that Nicolaus Copernicus (1473-1543) was the first to propose the theory of geocentrism. However, more than 1700 years before Copernicus, the ancient Greek astronomer Aristarchus (310 BC-230 BC) had proposed that the center of the universe was the sun and that the earth and planets revolved around it. However, his theory went unnoticed in ancient Greece because the society was not ready for geocentrism and there was not enough astronomical evidence to support it. Over time, humans accumulated astronomical observations and astronomical knowledge, and in 1543, Copernicus codified his theory in his book On the Rotation of the Earth. However, his theory was not accepted at the time because it was limited by the need to add a mains power source to explain the motions of the heavenly bodies.
This is when the German scientist Johannes Kepler (1571-1630) became impressed with Copernicus’ theory and began to study astronomy. In 1609, Kepler proposed a theory of geocentrism that complemented Copernicus’ theory, and although it was opposed by some, its theoretical completeness greatly increased its supporters.
The belief that God and humans were at the center of the world was dominant at the time of Aristarchus, Copernicus, and Kepler’s arguments, and this belief had a major impact on whether or not the paradigm was accepted by the scientific community. Whereas Aristarchus’ and Copernicus’ geocentrism fell out of favor, Kepler’s geocentrism was accepted because of the vast amount of astronomical knowledge that had been accumulated and the completeness of Kepler’s theory. There are records of Kepler being influenced by sun-worship ideas in his transition to geocentrism, but this seems to have been the case for only a few pioneering scientists. The vast majority of scientists will choose a new paradigm based on the rational explanations it offers and the limitations of the old paradigm. To the extent that paradigm shifts are driven by the rational judgment of the majority of the scientific community, it can be argued that, in the long run, scientific progress is driven by rational factors, contrary to Kuhn’s claim.
For the above argument to hold, there must be a rational standard against which the old paradigm and the new paradigm can be compared. According to Kuhn, the two paradigms are incomparable, so there is no rational basis for comparison. However, consider the goal of science: to gain knowledge of natural phenomena and organize it through experimentation and verification. Paradigms emerge within the larger framework of science, and each paradigm has the goal of providing a rational explanation of natural phenomena, even if they differ in the direction of normal science. Two paradigms can be compared based on which one explains natural phenomena more rationally and provides a suitable model. Thus, a society of scientists can rationally choose a paradigm, and scientific progress can be said to be rationally guided by accumulated knowledge and theories.
Kuhn interpreted the structure of scientific revolutions to mean that scientific progress is not driven by accumulation toward truth, but by periodic revolutions. He argued that there is incomparability between old and new science before and after scientific revolutions, and that scientists do not choose paradigms based on rational evidence, but on irrational factors such as religious conversion. Kuhn’s argument is important because it shook up the belief that science is absolute truth. However, given the goals of science, there is comparability between the two paradigms, and the progress of science can still be seen as rational in the long run for a society of scientists. I think Kuhn’s claim that scientific progress is irrational is extreme, but it is important in that it made me rethink my blind faith in science as absolute truth.
