3 The New York Years (1931–1953)

354 11 History and Philosophy of Biology—Mayr’s Third Synthesis
at the organismic level. Darwin’s views on classification, the “Natural System,”
are being discussed controversially. Whereas Mayr (1969b, Mayr and Bock 2002h)
contended that Darwin had proposed to take into consideration both common
descent (genealogy) and morphological divergence of sister taxa, Ghiselin (2004)
quoted from Darwin’s publications suggesting that classifications should reflect
exclusively genealogy.
The term “Darwinism” has several different meanings: Darwinism as selectionism
is true today and since the Evolutionary Synthesis (Synthetic Darwinism,
Junker 2004). During the late 19th century, this was also true for Weismann, Wallace
and several other early naturalists. August Weismann, the most important
evolutionist immediately after Darwin, showed (for animals) that the germ line
and the somatic line are strictly separated and, therefore, he rejected the inheritance
of acquired characters (Mayr 1985i). Darwinism as variational evolution
refers to the non-essentialistic tenets of this theory. Darwinism as the creed of
the Darwinians refers to their rejection of special creation; he who believed in the
origin of the diversity of life through natural causes, was a Darwinian. Darwinism
signified the destruction of the previously ruling worldview. Neo-Darwinism as
practiced by August Weismann since 1883 is Darwinism without ‘soft’ inheritance,
the inheritance of acquired characters.
Book reviews. Mayr’s reviews of newly published books on Darwin and Darwinism
are more than mere descriptions of their contents, because he used these
opportunities to point out to his readers the continuing relevance of Darwin’s
ideas which far transcends evolutionary biology. In 1971(j) he referred to the
publication of Darwin’s correspondence and portions of the Darwin papers in
the library of Cambridge University (including the Notebooks). At first Mayr had
thought that nominalism (“only individuals exist”) had something to do with Darwin’s
introduction of population thinking, but he did not find any support for
this suggestion in the writings of any author influenced by nominalism. Instead,
population thinking probably originated among the naturalists [who began to
collect “series” (population samples) of specimens during the mid-19th century]
and among the animal and plant breeders. Mayr here quoted Darwin’s letter to
Asa Gray (20 July 1856): “My notions about how species change are derived from
long-continued study of the works of […] agriculturists and horticulturists.”
In his review of David Hull’s book, Darwin and his Critics Mayr (1974k) emphasized
that Darwin, in 1859, forced his readers to choose one of three alternatives:
(1) Continuing creation of species and their adaptations, (2) teleological evolution,
or (3) evolution by random variation and natural selection with no recourse to any
supernatural intervention, even at the beginning. In each of 12 detailed contemporary
reviews of the Origin assembled in Hull’s book creationism is prominent.
Mayr admitted that Darwin provided little evidence for the change of one species
into another in succeeding geological strata or the production of new structures
and taxonomic types by natural selection (historical evolution). Also, Darwin left
unanswered the origin of life and of new genetic variation, and he was confused
about certain problems. The four favorable reviewers of the Origin still did not feel