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The disunity of science is a feature, not a bug

Mathematical models wield miraculous power, but mistaking them for reality has trapped science in a destructive quest for a “Theory of Everything.” Physicist and philosopher Ragner Fjelland argues that this leads to bloated, Frankenstein theories kept alive by clumsy, ad-hoc amendments, which reduce rather than boost science’s power. Fjelland calls for a radical shift in our attitude: we must reorientate towards creating entirely new theories, celebrating rather than lamenting disunity and diversity in science. Science, from the scientific revolution in the seventeenth century to the present day, has more or less developed in a “reductionist” way. The fundamental assumption is that all sciences may be ordered in a hierarchy that can be represented as an upside-down pyramid. At the top we find the human sciences, and at the bottom physics. Strong (or “ontological”) reductionism maintains that all theories at one level can be completely reduced to the lower level, all the way down to theories of atoms and elementary particles, or whatever is “at the bottom.” In the end, all diversity in the world can be unified in one fundamental theory. Hence it is called a final theory, or a Theory of Everything.One of the central figures in developing the idea of a Theory of Everything is the Dutch theoretical physicist Gerard 't Hooft, who received a Nobel Prize in physics in 1999 for his work. He emphasizes the non-empirical status of the theory:There exists no closely resembling alternative theory. This means that any slight change brought about in the rules would make the theory unlikely or inelegant. The theory will be a "package deal": take it, or leave it. This should hold both for the local laws and for the boundary conditions.This endeavor is not new. On the contrary, it goes all the way back to the birth of Western philosophy 2,500 years ago. The Babylonians made regular astronomical observations during a period of 600 years, from 747 BCE until 150 ACE. They developed mathematical techniques to predict astronomical phenomena, but they made no attempts at explaining them. However, the Greeks developed models, both material and theoretical, to explain the observed phenomena.The best example is Plato’s late dialogue Timaeus. Here he introduces a divine craftsman, the Demiurge, who has constructed the universe according to an original plan. Plato seems to have thought that the original plan is what is actually real, while the material world is merely an imperfect realization of it. He therefore does not, in the Timaeus, reconstruct the material universe, but the original plan, which can then be used to explain the material universe.Plato’s aim in producing a theoretical model is to reconstruct the original plan. That is what he carries out in Timaeus—and some modern physicists have embarked on the same project. For example, Einstein’s basic attitude is reflected in the title of Abraham Pais’ biography: “Subtle is the Lord...,” echoing Einstein’s comment, “Subtle is the Lord, but malicious He is not.” In an interview Einstein compared our situation to a child who enters a huge library. The child knows that someone has written the books, but he does not know the languages in which they are written. He suspects that there is a mysterious order, but he does not know what it is.___“We have all been working in what Husserl called the Galilean style; that is, we have all been making abstract mathematical models of the universe to which at least the physicists give a higher degree of reality than they accord the ordinary world of sensation.”Steven Weinberg, Nobel Prize in Physics (1979)___This Platonist view is contrary to a widespread impression of science, symbolized by the picture of the “father” of modern science, Galileo Galilei, with his telescope. According to this impression, Galileo liberated himself from the dominating metaphysics of his day—basically Aristotelian philosophy—and constructed a telescope that he directed towards the sky, showing that Jupiter has four moons. He also performed experiments with bronze balls rolling down inclined planes and found the law of freely falling bodies.However, in other cases Galileo emphasized the unreliability of our senses. It is easy to see why. He defended Copernicus’ heliocentric hypothesis. According to this hypothesis, we are not at rest at the center of the universe, but moving at a tremendous speed through space. Why don’t we observe this motion? Galileo praises Copernicus because “with reason as his guide he resolutely continued to affirm what sensible experience seemed to contradict.” In other places he directly refers to Plato. SUGGESTED VIEWING The quest for a final theory With Michio Kaku Galileo’s Platonism goes back to his early writings. In The Assayer, published as early as 1623, Galileo compared the universe to a grand book that is written in the language of mathematics, and “its characters are triangles, circles, and other geometric figures without which it is humanly impossible to understand a single word of it.” Therefore, things that cannot be described by mathematics—for example, colors, smells and odors—are not real. They are merely subjective.This division into subjective and objective, advocated by Galileo and his younger contemporary René Descartes, is normally associated with a mechanistic world view, which is regarded as the opposite of Platonism. When we reduce something to, for example, molecules and atoms, we move “downwards.” In contrast, the Platonist moves “upwards,” to abstract entities. However, it only shows that when we address fundamental questions, we should be careful in applying everyday spatial metaphors like “up” and “down.”___Nature is complex, and we cannot in general construct mathematical models that adequately describe the world.___The endeavor of finding a Theory of Everything has been heavily criticized. In 2006, the theoretical physicist Lee Smolin published “The Crisis in Fundamental Physics.” He argued that one of the most fundamental principles of science is that we should only regard theories as scientific if we have the possibility to show that they are false by experiments. Although he did not refer to Karl Popper, other critics have referred to Popper and argued that a theory is not scientific if it cannot be falsified (see for example Ellis & Silk 2014).These were not the first physicists to be anti-reductionists. In 1972, the journal Science published an article by the physicist Philip Anderson with the title “More Is Different.” This is the kind of article a scientist would normally write only after he has won a Nobel Prize. However, Anderson won the Nobel Prize for physics five years later, in 1977. The article is amazing, not primarily because it argues in favor of anti-reductionism in general, but because it argues for anti-reductionism within physics itself. Anderson’s conclusion was:At each stage entirely new laws, concepts, and generalizations are necessary, requiring inspiration and creativity to just as great a degree as in the previous one. Psychology is not applied biology, nor is biology applied chemistry.We may say that Plato started the “unity of science movement,” based on Euclidean geometry as the model of all knowledge. A distinguishing mark of geometry is that all possible constructions can be reduced to a few fundamental principles. We have to acknowledge that this approach has limitations. In general, we can easily model technological systems. In addition, we may construct simplified and idealized models that capture important aspects of systems, from various perspectives and for various purposes. But nature is complex, and we cannot in general construct mathematical models that adequately describe the world. In a complex system, each level has its distinct, emergent, properties that are characteristic of this level. Therefore, a complex system should be investigated at different levels and from different perspectives. Instead of exclusively pursuing a scientific ideal based on the unity of science, we should acknowledge the diversity—or even the disunity—of science.

Dec 23, 2025 • 7:00 AM EST • Science • iai.tv