154 Speciesit is because his book On the Origin of Species changed every scientist’s way of look-
ing at species thereafter. He has been more closely scrutinized than anybody else, and
there is a wealth of material available. One thing that we should put out of our minds
from the beginning, though: it is not true that Darwin did not address the origin of
species in On the Origin of Species. The book is “one long argument”^5 on that very
point. Over and again, he discusses why species evolve to be distinct from parental
forms, and how they have done so. It is unclear to me how this idea gained currency.^6
Darwin’s views on species changed over time. In his earlier works he seems to
have treated species the same way as his teachers, unsurprisingly, as groups united
by some description—that which Mayr refers to as “typological, ‘non-dimensional’
species of local fauna.”^7 Since his views are often misrepresented^8 on the basis of
comments made in the Origin, this chapter will give an extensive and chronological
series of quotations from his published works, including his correspondence and the
Notebooks. While Kottler’s analysis is reliable, some features of Darwin’s views that
are further developments of the older notions of species and some of his comments
that are relevant to later debates, particularly over speciation, are to be found in com-
ments not discussed by Kottler, Mayr, or Ghiselin.^9
The Notebooks
Darwin first began thinking about the nature of species in his Notebooks in 1837 and- Kottler has investigated Darwin’s early views on species in the Notebooks B, C,
D, and E (labeled by Kottler I–IV, which I have relabeled conventionally).^10 These are
referred to as the “transmutation notebooks” since Darwin started them after he became
convinced by Gould’s investigations of the finches found on the Galápagos Islands, and
the tortoises and mockingbirds backed it up, that these were modified descendants of
South American colonists.^11 Once he started on the idea, his conjectures came thick and
fast: mammalian species were shorter lived than simpler forms because of their com-
plexity, domestic animals were able to revert to the wild forms, or at least live like them,
perhaps species had a vital force and a fixed lifespan?, and so on. In the Notebooks, he
noted the “repugnance” of species to intercrossing (all quotations from Kottler):
(^5) Mayr 1991.
(^6) Possibly it arose from a comment made in 1866 by John Campbell, the Duke of Argyll [Campbell
1884 , 240]:
(^) It will be seen, then, that the principle of Natural Selection has no bearing whatever on the Origin
of Species, but only on the preservation and distribution of species when they have arisen. I have
already pointed out that Mr. Darwin does not always keep this distinction clearly in view...
(^) More likely, though, it is due to the fact that the modern consensus is that species are formed
by allopatric isolation, and Darwin held, as we shall see, that they are formed by selection on
varieties, now called sympatric speciation. Coyne and Orr, for example, state that he “there-
fore conflated the problem of change within a lineage with the problem of new lineages”
[Coyne and Orr 2004, 11]. I demur: this was Darwin’s hypothesis, rather than his confusion.
(^7) Mayr 1982, 265.
(^8) See Kottler 1978 for a discussion, particularly 291f.
(^9) Ghiselin 1984.
(^10) Kottler 1978.
(^11) Desmond and Moore 1991, 224f.