In this blog post, we explore how scientific truth develops at the boundary between mainstream and non-mainstream theories, and the controversies that arise in the process.
Until the end of the 16th century, the theory that the Earth was the center of the universe and that the sun, stars, and planets revolved around it (geocentric theory) was firmly established in people’s minds. At that time, Galileo discovered, based on his observations of the heavens, that the Earth was not the center of the universe, but only one of many planets revolving around the sun (heliocentric theory). However, even though his findings were based on scientific data, it was difficult to change the long-held beliefs of people overnight. It is well known that Galileo, who was brought before a religious court, quietly said, “Nevertheless, the earth moves,” as he left the courtroom.
C.R. Darwin is a similar case. In his book On the Origin of Species, he explained the mechanism of adaptation and evolution of species through natural selection, i.e., the theory of evolution. Darwin argued that new species with characteristics suited to their environment emerged over a long period of time as the first species adapted to different environments. Today, there is little disagreement in the scientific community about the evolution of life, but in the 18th century, people believed in creationism, which held that all species were created by God, and Darwin’s claims sparked great religious controversy and opposition.
Although the theory of evolution, which was once considered unconventional, eventually surpassed creationism to become the mainstream theory, opinions within the theory of evolution itself diverged, leading to the emergence of mainstream theories (adaptationism, gene selection theory, etc.) and unconventional theories (anti-adaptationism, multilevel selection theory). As in the cases of Galileo and Darwin, it is very difficult to establish a new theory that differs from the mainstream theory, which is the prevailing belief of the people. However, just as the heliocentric theory and the theory of evolution, which were once considered wrong, were eventually proven to be true, scientific debates should be judged solely from a scientific perspective, excluding personal thoughts, ideas, and preferences.
From this perspective, I oppose adaptationism and gene selection theory, which form the mainstream of evolutionary theory, and support anti-adaptationism and multilevel selection theory. In this regard, I would like to summarize my thoughts after reading the book Darwin’s Table by Professor Jang Dae-ik of Korea.
Darwin’s Table is a book in the form of a fictional debate between evolutionary biologists gathered at the funeral of William Hamilton, considered one of the greatest evolutionary biologists since Darwin, discussing various issues in evolutionary biology. As the title suggests, the debate involves Darwin’s descendants who support his core concept of natural selection. Although they support the same theory, they fiercely debate their different opinions on its scope and interpretation. The Dawkins team, represented by Dawkins, supports the mainstream theory, while the Gould team, represented by Gould, supports the non-mainstream theory.
First, Dawkins takes an adaptationist stance on whether human language should be viewed as a result of adaptation to the environment or as a byproduct of intellectual development. Adaptationism is the view that most characteristics of biological species are the product of adaptation to the environment. However, I believe that human language is a byproduct of the process of adaptation to the environment.
First, human language organs are innate, which is also seen in other primates such as chimpanzees. In addition, although various creatures have their own vocal organs for communication, considering that primates, among other animals, have the most developed grammatical systems, and that humans have the largest brains and the highest intelligence, it is reasonable to view language as a product of human brain and intelligence development.
Second, experiments in which chimpanzees, one of the most intelligent animals after humans, were taught grammar and made sentences confirm that human language is the result of intellectual development. The human brain is about a quarter to a third larger than that of chimpanzees, and no matter how much they are taught, chimpanzees have limitations in language learning. On the other hand, humans can continue to create new sentences based on the rules they learn during their first few years of life. As humans grow and their intelligence develops, they can gradually learn more language rules, while other animals cannot learn much language because their intelligence development is minimal.
In response to this argument, adaptationists argue that the complexity and sophistication of language grammar can be seen as a trait that satisfies the conditions of adaptation, that is, it satisfies a certain level of complexity, and therefore human language can be seen as the result of natural selection. However, the criteria for “complexity” and “sophistication” used by adaptationists are vague, and depending on the subjective judgment of the person applying the criteria, all phenomena in the natural world can be interpreted as adaptation. Therefore, in order to supplement this logic, adaptationists need to present more evidence and clarify the criteria for “sophistication.”
Second, let us examine the phenomenon of ‘cooperation’ that occurs in the natural world. There are often cases where individuals cooperate with their peers or sacrifice themselves completely even though there is no benefit to themselves. Ants and worker bees are representative examples.
Regarding this phenomenon, Dawkins’ team, which advocates genetic selection theory, argues that “humans and all animals are genetic survival machines and merely vehicles for carrying genes,” putting forward genetic reductionism. They argue that the extreme self-sacrifice of worker ants and bees is for the purpose of spreading their genes. In response, Gould’s team argues that although evolution can occur at the genetic level, it is not necessarily limited to that level. They propose a theory of multilevel selection, which states that evolution can occur not only at the cellular, organ, and individual levels, but also at various levels, such as species, genus, family, order, class, and phylum.
I am in favor of multilevel selection theory. This does not mean that gene selection theory is entirely wrong, but rather that evolution occurs at various levels, from small strands of genes to the organs, individuals, and species of living organisms. It is true that genes are ultimately where changes occur through evolution, but it is important to note that evolution is not simply a change in genes, but a change through natural selection. The reason why organisms evolve is because their interactions with nature change in response to changes in the natural environment, and it is the entire organism, not the genes themselves, that interacts with the environment in this process.
As there is still a lack of evidence for evolution, the debate in Darwin’s Table is likely to continue. Although sufficient evidence has not been secured, the establishment of logical theories through productive debates such as those in this book will greatly contribute to the advancement of science related to the theory of evolution. Personally, I believe that there are still many phenomena that cannot be explained by adaptationism and gene selection theory, which may be evidence that these theories are not perfect. Rather than taking an overly exclusive stance toward non-mainstream theories, we can further advance scientific theory by analyzing the weaknesses of mainstream theories on the assumption that non-mainstream theories are correct.
