Ernst Mayr, one of the twentieth century’s greatest biologists, died yesterday at the age of 100. During his 80-year career in evolutionary biology, Mayr helped create the "Modern Synthesis" that knit genetics, paleontology, and systematics together under the umbrella of Darwinian evolution. Virtually all of modern biology owes a tremendous debt to Mayr and his colleagues in the Synthesis (e.g., Wright, Dobzhansky, Stebbins).
Beyond that debt, Mayr occupied a unique place in modern biology due to the breadth of his work. He pioneered the analysis of species diversity and the role of geographic separation in speciation. But most importantly in my view, Mayr sharpened our understanding of the philosophical issues underlying the Darwinian conception of the natural world. His 1959 article, Typological and Population Thinking, was the first recognition that Darwin had ushered in not just a new scientific theory but one that relied upon a new way of understanding variation and change. Mayr noted that the shift from "typological" to "population" thinking, or in other terminology, the rejection of Aristotelian essentialism, was crucial to understanding how variation was causal in evolution, instead of merely noise around unchanging "kinds" or "types." This realization is deeply woven into modern biology, even if this lesson has yet failed to completely penetrate Western culture and common sense.
Furthermore, Mayr wrote widely and deeply about the history and philosophy of biology. His Growth of Biological Thought remains a key resource and my well-thumbed copy occupies pride of place on my biology shelves. In his historical and philosophical work, Mayr also fought against the teleological tradition both in biology and in Western culture. The following made a deep impression upon me, both in scientific and political outlook:
In the case of teleology, Darwin clearly placed a burden upon us. We can no longer rely on the assumption that no matter what we do, everything will surely in due time become better and better….Even though Voltaire in his satire Candide exaggerated the thinking of a cosmic teleologist, there is no doubt that there is no validity whatsoever in any form of panglossianism. If we want to have a better world, it is up to us to take the necessary steps. We must revise our ethical principles. We must begin to think more of the future of mankind as a whole, or even simply of the future of our community, our population, and take the necessary steps even though they may be painful for the individual. This lesson is perhaps the most difficult consequence of Darwin’s theories. (1)
Truly, Ernst Mayr was a giant among scientists. He was of a generation when one man, particularly one with his breadth of intellect and interests, could help radically transform the entire field of biological endeavor. Few do so, but Mayr did, and left biology a much richer discipline for his 80 years of thought, observation, and dedication.
(1) Mayr 1995, "Darwin’s Impact on Modern Thought," Proceedings of the American Philosophical Society, p. 317-325.