Species

Darwin and the Darwinians 183

interpretation,^104 which is to my mind clearly a strawman interpretation based on
Engels’ own ignorance of the use of the French term sol by Buffon and others to
mean “habitat.” In his 1865 work there is an extended discussion of the definitions of
“species,” the first such discussion I know of, mostly focusing on French definitions
from Cuvier onward. It is possible, although there is no direct evidence as yet, that
Wagner also had read Trémaux’s ideas when he  published three years afterward.
Trémaux later published a more “cosmic” form of his ideas,^105 which are reminiscent
of Spencer’s cosmic evolution.

Wallace and Weismann’s Adaptationist Definition

Alfred Russel Wallace (1823–1913), co-discoverer of natural selection as an agent of

evolution with Darwin, never really admitted the action of anything else in evolu-

tion. It followed, therefore, that he would insist that natural selection was the agent of

speciation, and hence that species are to be identified with their special adaptations.

Before he had gone public with his own evolutionism, Wallace asked if there was only

an indefinable amount of difference that separated permanent varieties from species:

If there is no other character, that fact is one of the strongest arguments against the

independent creation of species, for why should a special act of creation be required to

call into existence an organism differing only in degree from another which has been

produced by existing laws? If an amount of permanent difference, represented by any

number up to 10, may be produced by the ordinary course of nature, it is surely most

illogical to suppose, and very hard to believe, that an amount of difference represented

by 11 required a special act to call it into existence.^106

Kottler describes how Wallace’s idea of species in this period involved lack of

interbreeding, like Darwin’s: “contact without intermixture being a good test of spe-

cific d i f ference.”^107 In his Darwinism he defined species as

An assemblage of individuals which have become somewhat modified in structure,

form, and constitution, so as to adapt them to slightly different conditions of life; which

(^104) Two exceptions: Diane Paul [1981], and Stephen Jay Gould [1999]. Gould, however, seems to have
wanted to distance himself from the Engels’ misinterpretation of Trémaux in order to shield punctu-
ated equilibrium theory from another charge of being unsupportable, and so he says:
(^) I had long been curious about Trémaux and sought a copy of his book for many years. I finally
purchased one a few years ago—and I must say that I have never read a more absurd or more
poorly documented thesis. Basically, Trémaux argues that the nature of the soil determines
national characteristics and that higher civilizations tend to arise on more complex soils formed
in later geological periods. If Marx really believed that such unsupported nonsense could
exceed the Origin of Species in importance, then he could not have properly understood or
appreciated the power of Darwin’s facts and ideas. [page 90]
(^) In fact, we think that Marx had the right of it. Trémaux actually is putting forward a mechanism
for speciation that explains species (at least, of animals) and human geographical differentiation
[Wilkins and Nelson 2008]. By failing to read sol (soil) as a general term for habitat rather than, as
Engels did, a term for “geological formations,” Gould unfairly dismissed Trémaux.
(^105) Trémaux 1874.
(^106) Wallace 1858; quoted in Kottler 1978, 294.
(^107) Kottler 1978, 295.