Species

180 Species

the sexual organs and the structures of the organisms, although he rejected it in
a particular case.^89 Nevertheless, I think we can dispose of Futuyma’s and others’
mischaracterization. Darwin knew very well how to define species, given the fact
of evolution.
In summary, Darwin was a species realist, but denied the absolute rank of
Linnaean classification, although he used it in practice and was a contributor to the
Strickland Rules. He allowed for asexual species, and his views focused primarily on
the process of speciation, which he initially entertained might be due to geographi-
cal isolation (and possibly the effects of the local climate, as in the traditional view)
but later held was due to the fixing of subspecific varieties due to natural selection.
Speciation is a side-effect of selection between varieties that causes changes in the
sexual reproduction system of sexual species.^90

Interpretations of Darwin’s Idea of Species

Both historically and recently, Darwin has been variously interpreted on species.
We will deal with some of the historical cases below, but it is worth reviewing the
recent literature, as Darwin is something of a palimpsest in this, as other topics, on
which thinkers project their own views. We will see that around the end of the nine-
teenth century, it became the consensus that Darwin denied that species were real,
or that they had any special status in biology. However, the most influential writer
on Darwin’s supposed “species nominalism” has been Ernst Mayr, who published
numerous pieces claiming that Darwin had the “wrong view of species.”^91
Ernst Mayr held that Darwin had the “right” understanding of species, early
in his Notebooks, basing his claim on Kottler’s review of them. However, Mayr
thought Darwin “failed” because of his insistence upon the primacy of natural
selection:

Darwin succeeded in convincing the world of the occurrence of evolution and ... he

found (in natural selection) the mechanism that is responsible for evolutionary change

and adaptation. It is not nearly so widely recognized that Darwin failed to solve the

problem indicated by the title of his work. Although he demonstrated the modification

of species in the time dimension, he never seriously attempted a rigorous analysis of

the problem of the multiplication of species, the splitting of one species into two.

...

In retrospect, it is apparent that Darwin’s failure ... resulted to a large extent from

a misunderstanding of the true nature of species.^92

As Mayr was an advocate of allopatric speciation as the major, if not sole, cause
of speciation, natural selection, which required sympatry, was not the cause of
new species; hence Darwin was wrong. However, Mayr held, Darwin did get right

(^89) Da r win 1875, vol. II, 413.
(^90) A slightly different interpretation is given by Mallet 2008.
(^91) Mayr 1942, Burma and Mayr 1949, Mayr 1957, 1959, 1982.
(^92) Mayr 1963, 12, 14. Quoted in Mallet 2013.