Abstract

As one of the preeminent evolutionary biologists of the 20th century, Ernst Mayr's work as a scientist has received attention from both historians and philosophers of science. For example, Mayr's contributions concerning the biological species concept, geographic speciation, and the evolutionary synthesis continue to inform historical and philosophical analyses. But Mayr's importance goes beyond simply that of a prolific biologist whose work provides raw materials for historians and philosophers. Indeed, Mayr is one of the few biologists who has also made significant contributions to the history and philosophy of biology. Given his expertise and authority as a practicing evolutionary biologist, it is not surprising that Mayr's contributions concerning the history of Darwinism, the concept of natural selection, teleology, the autonomy of biology, proximate versus ultimate causation in biology, and the typological/population distinction have been influential. Of these topics, Mayr makes his boldest philosophical claims for the typological/population distinction. For Mayr, typological thinking is simply the application of Platonic essentialism to biological variation. The typologist ignores the biological significance of variation and focuses on underlying types. Population thinking, on the other hand, acknowledges the fundamental importance of variation and focuses on the properties of unique individuals and populations of such unique individuals. My dissertation provides a systematic and critical analysis of Mayr's distinction between typological and population thinking in biology. In particular, I discuss Mayr's first publications on the distinction, present the historical development of the distinction in Mayr's work on species, and trace his use of the distinction in three case studies: the relationship between genetics and evolutionary biology, the classical/balance controversy within evolutionary biology, and human racial variation. While Mayr contends that population thinking has replaced typological thinking in biology, my analysis casts doubt on this claim and points to a more complicated relationship between the two. I argue that refined versions of typological thinking persist in biology and that it is the ongoing interaction between typological and population thinking that needs to be scrutinized in order to understand the development of 20th century biological science