In this blog post, we will examine how evolutionary theory has developed since Darwin and explore what we have learned and gained—in terms of the relationship between science and faith—amidst the long-standing debate with creationism.
There were certainly people who advocated for evolution even before Darwin, and they did indeed exist. So why do we recognize Darwin as the first proponent of evolutionary theory? This article aims to provide detailed information on evolutionary theory, including its origins and development, the specifics of the theory, and comparisons with other theories. Before beginning, I will explain the definition of evolutionary theory and the scope of the theory covered in this article. Evolutionary theory has both a narrow and a broad meaning: in the narrow sense, it refers to the theory concerning the factors of biological evolution, while in the broad sense, it refers to the academic field that studies biological evolution. The evolutionary theory discussed in this article refers to the former.
In the mid-18th century, signs began to emerge in France that foreshadowed the advent of a new science. As the concept of causal change in nature became established through the spread of Newtonian mechanics, a transformation took place as if a vast blueprint were unfolding. From Maupertuis, who wrote works containing the principle of natural selection, to Olbach, who argued that humans are the product of nature’s historical changes, the attempts of various scientists indicate that a new ideology, distinct from creationism, was beginning to emerge at that time. However, they did not fully grasp the blueprint of this new theory known as evolutionary theory. Later, Lamarck was the first to systematically organize evolutionary theory, thereby fully realizing the blueprint of the theory. Lamarck argued that “all living beings evolve toward more complex and perfect forms,” naming this property “progressiveness” and identifying it as the primary cause of evolution. Furthermore, Lamarck proposed the “use-and-disuse theory”—that frequently used organs develop while unused ones degenerate—as the direction of evolution.
However, the figure who actually completed and widely disseminated the theory of evolution from this blueprint was Charles Robert Darwin (C.R. Darwin), who established the theory. The Darwin we commonly know is Charles Robert Darwin, the author of *On the Origin of Species*. Although his grandfather, E. Darwin, was also a proponent of the theory of evolution, all subsequent references to “Darwin” refer to C.R. Darwin. Darwin rejected Lamarck’s theory of use and disuse, instead identifying natural selection—based on variability and its inheritance, as well as the finite nature of resources—as the primary cause of evolution. The core tenet is that, according to the principle of natural selection, the fittest survive over time. Although Lamarck and Darwin advocated different ideas, it was through them that the theory of evolution first emerged in the world.
Just as a gun is refined and develops into various forms, the theory of evolution has also continued to evolve since Lamarck and Darwin. Various theories emerged during this process. For example, Wagner and Gulick emphasized the importance of geographic isolation in speciation, while Negelli and Aimer focused on research into the direction of evolution, Kopf, who proposed Neo-Lamarckism—arguing that evolution occurs as a result of the inheritance and accumulation of traits acquired by organisms through experience; Weismann, who advocated for Neo-Darwinism by adding genetic concepts to Darwin’s theory of evolution; and Mendel, famous for his pea experiments—all put forward various theories.
In particular, Weismann’s “germ-layer” lecture and the rediscovery of Mendelian genetics in the 1900s had a significant impact on genetics. Weismann proposed that only germ cells are inherited across generations, while somatic cells are not, thereby providing evidence to refute Lamarck’s theory of use and disuse, which posited that acquired traits are inherited. Mendel’s theory of genetics, based on extensive experimental and statistical data, contributed significantly to the development of the chromosome theory.
By the 1930s, attempts to synthesize evolutionary theory began with Dobzhansky’s book *Genetics and the Origin of Species* (1937). The main tenets of the synthetic theory include organizing and expanding concepts from paleontology and biology centered on chromosome theory, population genetics, and the concept of species; rejecting the inheritance of acquired characteristics; explaining the gradual nature of the evolutionary process and mutations; and asserting that the direction of evolution is determined by natural selection. This effort highlighted the indispensability of evolutionary explanations in biology and served as a new starting point for evolutionary research. From the 1960s onward, the development of evolutionary theory accelerated based on advances in microscopy and analytical techniques, as well as research findings, giving rise to various debates. Notable among these were debates over whether evolution is regular and gradual or irregular and radical, and debates over whether the unit of natural selection is the individual, the population, or the gene. In particular, the debate over the unit of natural selection has been a central point of contention in evolutionary theory, spanning the period before the discovery of genes to the period following their discovery. Darwin advocated for an individual-centered theory, while Lorenz, Wyn Edwards, and Wilson supported group selection, and Hamilton and Dawkins championed the gene theory; this debate continues to this day among prominent scholars.
Thus far, I have briefly outlined the history of evolutionary theory and compared the various theories within it. However, while these internal debates are based on the premise that evolutionary theory is correct, there exists a broader debate that does not rely on such a premise. This involves debates with theories other than evolutionary theory, and among these, the debate with creationism has persisted from the very beginning of evolutionary theory to the present day. I will now begin to explain this.
Like other major scientific theories, evolutionary theory began amid significant opposition. Just as the geocentric model rejected the heliocentric model, creationism rejected evolutionary theory, arguing that the claim that humanity’s ancestors were not Adam and Eve constituted a blasphemy against the Bible. However, since scientifically proven facts cannot be denied on the basis of religious dogma alone, religions such as Christianity abandoned the geocentric model. Similarly, while Adam and Eve were once accepted as humanity’s ancestors, they have come to be viewed as symbolic figures after it was proven that the Earth and humanity already existed 6,000 years ago—the time of their supposed creation. Of course, creationism has not disappeared entirely; even though some of its tenets are acknowledged, it continues to engage in debate with proponents of evolutionary theory to this day. This is because while evolutionary theory can adequately explain “microevolution”—the development within a species—it struggles to explain “macroevolution”—the differentiation from one species to another. Modern creationism has now moved beyond simple religious assertions to put forward certain theories based on science, and in fact, it accepts microevolution. Therefore, the main differences between modern creationism and evolutionary theory lie in whether life was created from nothing and whether evolution occurs from one species to another. There are various theories within creationism itself, and while there have been attempts to fuse the two by introducing the concept of “creationism,” these are omitted here as they are not directly relevant to the topic of evolutionary theory discussed in this article.
No theory in the world is perfect. Even Newtonian mechanics, which seemed highly suitable both empirically and intuitively, was revealed to be incomplete by quantum mechanics and the theory of relativity; furthermore, since quantum mechanics and the theory of relativity contain contradictions that make them mutually incompatible, it is believed that at least one of them—or both—must contain errors. Even mathematics, which has been proven to be eternally true, still has unresolved problems in its unproven areas. However, just as a test score that isn’t a perfect 100 is not meaningless, a theory has clear significance even if it is not perfect. All theories undergo continuous development. Similarly, theories regarding the origin of life, including the theory of evolution, will continue to evolve as remaining problems are resolved through rediscovery, the emergence of new theories, and discoveries driven by scientific progress. Through this process, we will come to understand much more about the past.
