charles_darwin

The Origin of Species
(1776–1847) wrote books on the natural history of horses, dogs, and
pigs in 1834, 1845, and 1847, but he left untouched the question of
a unifying theory connecting all species. That was the difficult task
Darwin undertook in The Origin of Species.
Again, Darwin was not the first to consider a grand theory of
nature. Leaving aside famous philosophical works dating back to
Aristotle’s Physics, in the nineteenth century, there was Chambers’s
Vestiges of the Natural History of Creation. There were also lesserknown
and much less controversial works. Charles Hamilton Smith
(1776–1859), author of several books in a series entitled The Naturalist’s
Library, wrote The Natural History of the Human Species, its
Typical Forms, Primaeval Distribution, Filiations, and Migrations
(1848). William Martin (1798–1864), another author of several natural
history books, wrote A General Introduction to the Natural History
of Mammiferous Animals, with a Particular View of the Physical History
of Man, and the More Closely Allied Genera of the Order of Quadrumana,
or Monkeys (1849). Both of these books were progressivist:
they attempted to demonstrate that humans were at the top of the
scale of organic beings.
Darwin took the opposite approach in The Origin of Species.
The differences between species and the variations of species did not
prove that one species was superior to another; rather, variation was
evidence of the process of evolution at work. Variation was linked to
common origins not necessarily to a scale of being.
The first points Darwin makes in the opening chapters of The
Origin of Species are about the individual characteristics of animals
and plants. Given the debate about origins, Darwin had to explain
the differences between the species and their varieties. Were the differences
permanent, part of a preestablished order, or was nature in
a constant state of change? If there was continual change, how was
this change produced? Was the change (that is, the mutation) passed
on to other members of a species and could the mutation lead to
transmutation?
By the end of the fifth of fourteen chapters, Darwin had
answered these questions. The title of Chapter VI, ‘‘Difficulties on
Theory,’’ is the clue. In Chapter VI, Darwin dealt with the ‘‘crowd of
difficulties’’ that he thought a reader of The Origin of Species would
have. 23 Darwin’s primary concern was to prove that mutation occurs
in organic life and that this fact was significant to understanding the
origin of species: he believed he had already accomplished this by
the beginning of Chapter VI.
The structure of the argument Darwin used to prove his theory
was significant. In Chapter I, ‘‘Variation Under Domestication,’’
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