In this blog post, we will examine why scientific truth often originates in the fringe and explore how this pattern appears in the evolution debate.
Until the late 16th century, the geocentric model—the belief that Earth was the center of the entire universe and that all stars and planets, including the Sun, revolved around it—was firmly entrenched in people’s minds. At this time, Galileo, based on his observations of celestial bodies, revealed the heliocentric model: that Earth was not the center of the universe, but merely one of several planets orbiting the Sun. However, despite presenting scientific evidence, it was difficult to instantly change ideas that had been ingrained in people’s minds for centuries. The famous anecdote of Galileo, after being tried by the Inquisition, quietly muttering “Nevertheless, the Earth moves” as he left the courtroom, is well-known.
Charles Darwin’s case was similar. In his book On the Origin of Species, he explained the mechanism of adaptation and evolution of species through natural selection—the theory of evolution. He argued that as the earliest species lived in different environments and adapted over long periods, new species with characteristics suited to their environments emerged. While there is now no disagreement within the scientific community about biological evolution, people in the 18th century believed all species were created by God. His claims thus sparked immense religious controversy and backlash.
Thus, while evolutionary theory—once a fringe idea—overcame creationism to become mainstream, opinions within the evolutionary framework later diverged, splitting into mainstream theories (adaptationism, gene selection theory, etc.) and non-mainstream theories (anti-adaptationism, multilevel selection theory). As seen in the cases of Galileo and Darwin, establishing a new theory that differs from the prevailing ideas—the mainstream theory—is an extremely difficult task. However, just as the heliocentric theory and evolution, once deemed incorrect, were ultimately proven true, debates over scientific issues should be judged solely from a scientific perspective, excluding personal thoughts, ideologies, and preferences.
From this scientific perspective, I oppose the adaptationism and gene selection theory that currently dominate evolutionary theory, and instead support anti-adaptationism and multilevel selection theory. In relation to this, I wish to share my thoughts after reading the book ‘Darwin’s Table’.
Darwin’s Table is a book presented as a fictional dialogue among leading evolutionary biologists attending the funeral of William Hamilton, considered the greatest evolutionary biologist since Darwin. They discuss various contentious issues within evolutionary theory. As the title suggests, participants include Darwin’s descendants who accept the core concept of his theory: natural selection. Though they share the same theory, they differ in its scope and intensity, engaging in fierce debates on each aspect. The Dawkins team, represented by Dawkins, supports the mainstream theory, while the Gould team, represented by Gould, supports the non-mainstream theory.
First, regarding whether human language should be viewed as an outcome of adaptation or a byproduct of intelligence development, Dawkins takes an adaptationist stance. Adaptationism is the position that most characteristics of biological species are the result of adaptation to their environment. However, I oppose this view, believing language is a byproduct of humans adapting to their environment. First, the human language apparatus is innate and appears in similar forms in other primates like chimpanzees. Furthermore, other organisms besides primates possess various forms of communication and the vocal organs necessary for it. However, considering that primates, and among them humans, have the most developed grammar compared to other organisms, and that humans possess the highest level of brain development and intelligence among all animals, it is reasonable to view human language as a phenomenon arising from brain development and the evolution of intelligence. Second, experiments teaching chimpanzees—one of the most intelligent animals after humans—human grammar to construct sentences also confirm that human language stems from intellectual development. Despite extensive training, chimpanzees, whose brains are only one-quarter to one-third the size of a human brain, face inherent limitations in acquiring language. In contrast, humans can continuously generate new sentences using rules learned within the first few years of life. Humans develop intelligence up to a certain point during growth, enabling them to learn more language rules. In contrast, other animals have inherently lower intelligence and minimal developmental capacity, preventing them from acquiring extensive language.
Regarding the above argument, proponents of the adaptationist position may counter that the complexity and sophistication of linguistic grammar satisfy the criteria for traits considered ‘adaptive’—namely, a threshold level of complexity—and thus human language can be viewed as an adaptation resulting from natural selection. However, the criteria for ‘complexity’ and ‘sophistication’ invoked by adaptationists are highly ambiguous. Depending on the subjective judgment of the human applying these criteria, virtually any phenomenon in nature could be interpreted as an adaptation. To develop this argument further, adaptationists need to find more evidence and define the criteria for ‘sophistication’ more precisely.
Second, let us examine the phenomenon of ‘cooperation’ observed in nature. There are frequent instances where individuals cooperate with others or make complete sacrifices despite receiving no personal benefit in return; worker ants and worker bees are prime examples.
Regarding this phenomenon, the Dawkins team, advocating gene selection theory, asserted “humans and all animals are merely survival machines and carriers for genes,” promoting gene reductionism. They argued that even the extreme self-sacrifice of worker ants and bees is solely for the purpose of spreading genes more widely. In response, the Gould team counters that while evolution can occur at the gene level, it is not necessarily confined to that level alone. They argue that evolution can occur at the cellular, organ, and organism levels that compose living beings, and at every level of biological classification: species, genus, family, order, class, phylum, and kingdom. This is called multilevel selection theory.
Personally, I tend to support multilevel selection theory. To be precise, I don’t believe gene-centered selection theory is entirely wrong; rather, I think the levels at which evolution occurs are highly diverse, ranging from small strands of DNA to individual organs, organisms, species, and beyond. It is true that genes are where changes ultimately occur through evolution. However, we must note that evolution here does not simply mean the evolution of genes, but rather evolution through ‘natural selection’. The cause of organisms evolving is changes in their interactions with nature due to shifts in the natural environment. In this process, it is the entire organism, not the genes themselves, that directly interacts with the natural environment.
Given the current scarcity of evidence for evolution, the debate in ‘Darwin’s Table’ is likely to persist. Although evidence is limited, productive debates like those in ‘Darwin’s Table’ can significantly contribute to the development of evolutionary science by helping establish logical theories. However, in my view, many phenomena remain unexplained by the mainstream theories of adaptationism and gene selection theory, suggesting these theories are not perfect. Rather than taking an exclusive stance against other theories, considering the possibility that non-mainstream theories might be correct could help identify weaknesses in mainstream theories and further advance scientific theory.
