This blog post examines, from philosophical and scientific perspectives, whether invisible theoretical entities like quarks and electrons actually exist or are merely scientific assumptions for explanation.
In Conan Doyle’s stories, Sherlock Holmes tracks down clues to crimes and solves cases with remarkable insight and observation. Holmes’ explanations are always more sophisticated and comprehensive than those of the police, and in the process, people become convinced his explanation is the most correct even before the culprit is arrested. Similarly, if one claim is relatively more explanatory than other explanations, we consider it to have a rational basis for acceptance. This mode of reasoning is called ‘Inference to the Best Explanation’.
Inference to the best explanation has been particularly useful in the realm of science. In science, competing theories often coexist when attempting to explain a phenomenon. This method works effectively when deciding which theory to adopt among those that are difficult to verify directly. For example, if a scientific theory can explain the same phenomenon more successfully than other theories, we can judge that theory to be more likely to be true. This serves as a practical criterion for judgment in the scientific inquiry process and has played a crucial role in driving scientific progress.
This mode of reasoning also serves as a key justification for advocating scientific realism. Scientific realism is a perspective premised on the belief that scientific theories do not merely serve as useful predictive tools, but rather truthfully, or at least approximately, describe the actual structure of the external world. Furthermore, according to this theory, the theoretical entities appearing within scientific theories—such as electrons, neutrinos, quarks, etc.—are not mere fictions for explanation, but representations of actually existing things.
However, directly observing or empirically verifying these entities in reality is extremely difficult. For instance, while quark theory successfully explains microscopic physical phenomena occurring within atomic nuclei, quarks themselves cannot be directly observed with current scientific technology. Nevertheless, we believe quarks actually exist and accept that quark theory provides an approximate yet true description of the natural world. This is the core of the realist perspective, which views scientific theories not as mere hypotheses but as truthful accounts of the real world.
Because scientific theories often involve principles or entities in nature that we cannot directly observe, they are frequently described in abstract language. Even amidst this abstraction and uncertainty, scientists evaluate a theory’s truthfulness through inference to the best explanation. Realists believe scientific theories reflect the structure of the actual world to some degree, finding justification for this belief in the successes of scientific theories. For instance, astronomical theories based on heliocentric models have provided far more accurate explanations and predictions than those based on geocentric models or astrology. This supports the belief that scientific theories accurately describe the real world.
Looking back at the history of science, numerous scientific theories have repeatedly been tested, revised, and achieved success. The sustained success of these theories is hardly the result of chance or luck. Realists argue precisely at this point that scientific realism offers the most compelling explanation for science’s remarkable achievements. That is, without the belief that the scientific theories we currently adopt are close to the truth, it is difficult to rationally account for the sustained success of scientific theories.
In conclusion, inference to the best explanation serves as a key tool supporting the philosophical justification of scientific realism. This not only logically supports the belief that scientific theories are converging toward truth, but it is also deeply connected to the way we reason in everyday life. Of course, scientific realism cannot be proven as clearly as a mathematical proof, but considering the achievements of science thus far and the persuasiveness of its theories, we can say we have sufficient reason to believe it is correct.
