Ornithology, Evolution, and Philosophy 123

Philosophy of Biology 361
At the University of Berlin in 1925/1926, Mayr took courses in the history of philosophy
and a seminar in Immanuel Kant’s Critique of Pure Reason but the teachers
made no attempt to indicate any connections between these philosophical topics
and biological problems. In his PhD examination in positivism he passed with an
A because he had been well prepared. The only books Mayr carried with him on
his expeditions to the forests of New Guinea in 1928–1929 were Driesch’s Philosophie
des Organischen (1899) and Bergson’s Schöpferische Entwicklung (1911), as he
mentioned in a letter to E. Stresemann dated 24 March 1934 (Haffer 1997b). By the
time he returned to Germany, he had concluded that neither Driesch nor Bergson
was the answer to his search (2004a: 2). He said that during the following 15 years
or so he more or less ignored philosophy. However, his discussions on the nature of
biological species, classification, and evolution during the early 1940s have a most
important bearing on the philosophy of biology. It is essential to realize the central
bearing of Mayr’s empirical work on the systematics and biogeography of birds on
his future thinking on the philosophy of science.
As editor of the newly founded journal “Evolution” (1947–1949) Mayr corresponded
with numerous zoologists on their work and, at the same time, began
to think in more detail about underlying historical and philosophical aspects. In
his letters to Professor Stresemann he commented on maturation of the species
concept and criticized that “the school of symbolic logic, started by the mathematicians
Bertrand Russell and Woodger, is now trying to invade biology with
a strictly static and formalistic philosophy. As one would expect from such a philosophy
they deny the existence of species. […] A small minority of biologists want
to take biology ‘back to nature’ ” (24 October 1949) and “I am afraid philosophy
has been rather a handicap in biological research as the writings of Schindewolf,
Beurlen, Dacqué and others [in Germany] prove” (20 November 1947).
Mayr never wrote a textbook on the philosophy of biology but his books, This
is Biology (1997b) and What Makes Biology Unique? (2004a) as well as many
papers on evolutionary theory summarize his thinking in this field and provide
a good overview. However, in view of his advanced age he was unable to develop
a coherent philosophy of science that included all aspects of biology (Bock 2006).
Mayr expressed his regret on not having published a book on the philosophy of
biology in his video interview in November 2003 (Bock and Lein 2005), and said
that he simply ran out of time.
Population Thinking
In several letters to Erwin Stresemann during the late 1940s, Mayr asked why the
Anglo-Saxons (Darwin, Wallace) rather than the continental European scientists
had found the right solution for the great problem of evolution and proposed that
they had always been interested in the study of populations and of variation unencumbered
by the idealistic philosophy of continental, especially German biologists.
As typologists, they had considered all biological phenomena as type phenomena
(letters dated 14 March 1949 and 14 December 1950). Mayr repeatedly referred