In this blog post, we will examine the truth of scientific theories and the reality of their objects of study, focusing on two questions raised regarding the epistemological status of scientific theories.
Science is deeply embedded in our lives. The spaces we inhabit, the food we eat, the clothes we wear—and even the substances that make up our bodies—are all subjects of scientific inquiry. Based on this inquiry, scientists develop various technologies, and people apply these achievements in their daily lives. It is no exaggeration to say that there are almost no areas untouched by science. However, perhaps because we have become so accustomed to the living environment shaped by science, people often struggle to answer the philosophical questions of what science actually is and why we pursue it. It is now time to take a step back and examine the concept of “science”—one we have always used so familiarly—from a distance. The aim is to reflect not only on the results of scientific inquiry but also on the essential meaning of science itself.
The “epistemological status of scientific theories” is a suitable topic for discussing the essence of science. In philosophy, “epistemology” refers to the concepts that provide the basis for a person to claim that a certain object is true. This meaning applies directly to science as well. The “epistemological status of scientific theories” is the concept that asks whether scientific theories and the concepts they contain can be subject to judgments of truth and falsehood. In science, specific objects or phenomena are primarily investigated through deductive and inductive methods. Regardless of the method used, when a new object is discovered or a new entity is proposed during the process of inquiry, a name is assigned to that object, and the results are organized into a single scientific theory that includes theoretical terminology. Here, the epistemological status of scientific theories raises two important questions. First, can we say that a scientific theory constructed in this way is literally true? Second, can we be certain that the objects referred to by theoretical terminology actually exist? Realists, instrumentalists, and technicalists (reductionists) offer different answers to these questions. To summarize their positions: regarding the first question, realists and technicalists answer in the affirmative, while instrumentalists answer in the negative; regarding the second question, only realists answer in the affirmative, while instrumentalists and technicalists answer in the negative.
Now, let’s examine the meaning of each question in turn and consider the answers.
First, let’s examine the first question: “Can we say that a theory is truly correct in the literal sense?” In the philosophy of science, theory and reality are viewed as distinct concepts. Realists argue that the truth or falsity of a theory can only be determined when it corresponds to the real world, and technicists also agree with this view. In contrast, instrumentalists view scientific theories as mere tools for explaining experience and the laws of nature; they argue that what matters is not whether a theory is true or false, but how useful it is for making predictions. Therefore, they contend that even if two theories appear to contradict each other at face value, they ultimately have the same meaning if they can explain the same observational results. They also argue that theories based on different paradigms are difficult to compare or interpret directly.
Let’s consider a simple example to illustrate this. Suppose there is a pot of freshly cooked rice, but we do not know what tool was used to cook it. One theory might explain that the rice was cooked in an electric rice cooker, while another might explain that it was cooked in a traditional earthenware pot. From a instrumentalist perspective, although the two explanations are literally different, they are both valid theories in that they ultimately explain the same observational result: “the rice was cooked.” In other words, since both theories serve the function of predicting the outcome, they are considered to have the same meaning.
However, the following question may be raised regarding this claim: How can a single serving of rice be both rice cooked in an electric rice cooker and rice cooked in a traditional pot at the same time? From a instrumentalist perspective, the scope of what can be definitively stated as true is necessarily extremely limited. In the actual process of cooking rice, whether using an electric rice cooker, a traditional pot, or some other cooking tool, exactly one tool must have been used. If an electric rice cooker was used, the term “electric rice cooker” in the first theory corresponds to reality, so that theory can be said to be true. Conversely, since the term “cast-iron pot” does not correspond to reality, that theory is false. Even if neither tool were used, neither theory corresponds to reality and thus cannot be considered true. Ultimately, in instrumentalism, the truth or falsity of a theory can be determined by examining how each theory corresponds to reality. Therefore, the answer to the first question can be considered “O.”
Next, let’s examine the second question: “Can we be certain that the theoretical objects referred to by theoretical terms actually exist?” A theoretical object refers to an entity posited by a scientific theory but cannot be directly observed. Electrons, quarks, genes, and dark matter are prime examples, and in the past, the ether and phlogiston were also included among such theoretical objects. Instrumentalists and technologists view these objects as merely concepts used to explain observable phenomena. Realists, on the other hand, argue that the theoretical objects addressed by scientific theories actually exist. Let’s examine this issue through a few examples.
First, consider the ether: the ether is a hypothetical substance that was once believed to fill all of space and serve as the medium necessary for the transmission of electromagnetic waves. From the late 19th century to the early 20th century, various studies were conducted to confirm its existence, but the Michelson-Morley experiment failed to find evidence supporting the existence of the ether. Subsequently, with the emergence of the “Special Theory of Relativity,” the concept of the ether became obsolete, and in modern physics, it is not recognized as a real entity.
Phlogiston is another similar example. In the 18th century, it was explained that when a substance burned, a substance called phlogiston, which existed within it, was released. However, actual experiments observed that the mass of the substance actually increased after combustion. Later, Lavoisier discovered that combustion is a chemical reaction with oxygen, and the phlogiston theory was discarded. These two examples demonstrate that while new concepts can be introduced to establish scientific theories, it cannot be assumed that those concepts necessarily exist in reality.
However, not all theoretical entities that appear in scientific theories have been discredited like the ether or phlogiston. There are also theoretical entities—such as electrons, radio waves, and viruses—that are accepted as real in modern science, and modern science and technology have advanced by understanding and utilizing the properties of these entities. In this regard, while empiricist technologists such as Van Fraassen argue that only what can be directly observed through human senses is real, technologists such as Ian Hacking maintain that objects which can be observed using human-developed observational equipment or manipulated experimentally are also real.
If we adopt the extreme technicist position—that only what can be directly verified by human senses is real—problems arise. Even if we observe cells or microorganisms under a microscope or examine microscopic structures using an electron microscope, we would fail to acknowledge their existence simply because they cannot be seen with the naked eye. This would make it difficult to explain a significant portion of modern science that studies the microscopic world. Furthermore, it would be impossible to adequately account for the numerous scientific and technological advancements developed using these objects.
For example, although plasmids and genes cannot be observed with the naked eye, modern life sciences experimentally isolate, manipulate, and utilize them. Scientists insert specific genes into plasmids to produce useful proteins and conduct various biotechnology research using genetic recombination techniques; these technologies are widely utilized in pharmaceutical development, agriculture, and industry. If plasmids and genes did not actually exist, it would be difficult to explain why these technologies function successfully.
Therefore, it is reasonable to acknowledge the existence of objects that can be experimentally manipulated and technologically utilized. From this perspective, the technocratic viewpoint proposed by Hacking is more persuasive than extreme technicism. However, this does not mean we can conclude that every theoretical object appearing in scientific theories necessarily exists. Therefore, the answer to the second question is “Δ.” In other words, while we cannot say that all theoretical objects exist, we must acknowledge the existence of those that can be observed or manipulated experimentally.
Earlier, we addressed the two questions raised by the “epistemological status of scientific theories”—namely, “Can we say that a theory is truly correct in the literal sense?” and “Can we be certain that the theoretical objects referred to by theoretical terms actually exist?”—with the answers “O” and “Δ,” respectively. Science is akin to the process of piecing together the countless puzzle pieces contained within nature, one by one. The scientific theories and theoretical objects created in this process can be described as systems and concepts constructed by humans to understand nature. Since theories can correspond to the real world, we can discuss whether they are true or false in and of themselves. However, not all concepts created by humans exist in the real world. This is because there are concepts—such as the ether and phlogiston—that were once used in scientific explanations but have since been discarded.
Therefore, when judging the reality of a theoretical object, it is necessary to consider both its observability and its experimental testability. For theoretical objects that cannot yet be directly observed or experimentally manipulated, it is preferable to leave them as possibilities to be verified through future research and evidence, rather than hastily concluding that they do or do not exist. Science is a discipline that is constantly being revised and developed, and existing theories can change in light of new evidence. For this reason, as we live in the age of science and technology, we should not merely make use of the achievements produced by science; rather, we must adopt an attitude of self-reflection and inquiry, asking ourselves what the essence of science is and what scientific truth entails.
