How a Japanese Scientist Took on Darwin and Won

Imanishi Kinji’s Innovative Environmental Philosophy of Coexistence

In 1984, British paleontologist Beverly Halstead (1933–1991) traveled to Japan to meet Imanishi Kinji (今西錦司, 1902–1992), a renowned Japanese biologist. The two men were opposites in nearly every respect. Imanishi was 82 years old — more than 30 years older than Halstead. Imanishi was Japanese, while Halstead was British. Imanishi devoted his life to studying living organisms and society, especially through his pioneering work in primatology and ecology. Halstead, by contrast, was a fossil specialist and defender of orthodox Darwinism.

With support from visiting professorships granted by British and Japanese institutions, Halstead traveled halfway around the world with one goal: to confront a man who had questioned fundamental principles of Darwinian theory. Notably, Imanishi was not a creationist; he believed in evolution. He argued that Darwinian theory needed critical revision. However, for Halstead, any deviation from strict Darwinism was scientific heresy.

In his article on the international reception of Imanishi’s research, Frans de Waal recounts this encounter:

In 1984, armed with a heavy load of prejudice and admitting no firsthand knowledge of Imanishi’s writings, Halstead came to confront Imanishi. In his unpublished English manuscript (a copy of which can be found in the Kyoto University Library), he noted: “In my Western way, I came to Kyoto, the home of Imanishi and his School seeking the man and his ideas, but I came as an avowed opponent” (Halstead 1984, unpublished manuscript). After handing the 82-year-old emeritus professor a gift — a bottle of whisky — he presented him with a document translated into Japanese containing statements such as “Imanishi’s evolution theory is Japanese in its unreality” and “You see the wood, but the trees are not in focus”. No wonder that Imanishi’s face, as Halstead recalled, betrayed profound regret at having agreed to the meeting. (De Waal, 2003, 293)

Ironically, since this meeting, many of Imanishi’s ideas have been adopted — often unknowingly — by Western researchers. We could say that Imanishi won in the most beautiful way possible: silently.

In what follows, I will first provide an overview of Imanishi’s life and academic career to contextualize his ideas. Then, I will examine two key concepts that constitute the core of his theoretical contributions. The first is sumiwake (棲み分け), or “habitat segregation,” which articulates a relational model of ecological differentiation. The second concept is his original conception of society, which he developed through the idea of the “society of a species” (shushakai 種社会) and extended to multispecies and planetary scales. Together, these notions allow for a radical rethinking of ecology and sociality in terms of interdependence rather than competition.