Species

104 Species

privative denitions—dened by what they are not.^252 He did also attempt a frag-
mentary “natural” system—one that grouped on all available characters—but spe-
cies remained those groups that shared all of some set of characters. Others, such
as Adanson,^253 based their classications on as many characters as could be used, in
an attempt to demonstrate natural groups. Arguably, Linnaeus succeeded more than
might be expected just from it being an arbitrary system.^254 So it is perhaps better
if we adopt the distinction between taxonomic and other logical essentialisms and
material essentialism, and see the former as a more or less conventional and harm-
less aspect of taxonomy, and the latter as something of a rare bugaboo.
I fully concur here with Winsor’s discussion^255 that the myth of essentialism in the
history of systematics is largely due to Joseph Cain’s 1958 paper “Logic and Memory
in Linnaeus’ System of Taxonomy,”^256 but I wonder also how much Popperian inu-
ence predisposed systematists to accept it and spread it. In any case, we have exten-
sively supported Scott Atran’s comment, quoted by Winsor:

For my part, I have so far failed to nd any natural historian of signicance who ever

adhered to the strict version of essentialism so often attributed to Aristotle. Nor is any

weaker version of the doctrine that has indiscriminately been attributed to Cesalpino,

Ray, Tournefort, A.-L. Jussieu and Cuvier likely to bear up under closer analysis.^257

I am unsure what Atran means by “weaker version”—there is, at least, a diag-
nostic essentialism, a taxonomic essentialism, in play with many authors, but only
a very few people, and perhaps only Nehemiah Grew, adopted any sort of material
essentialism that did not end up collapsing to a causal reproductive account, prior to
the Origin of Species. And when it existed, before or after, it was motivated by piety
rather than science. The transcendentalists however appear to be motivated also by
a neo-Platonic philosophy.

The Origins of Species Fixism

Species xism, the idea that species are as they have always been, appears to have

originated with Ray, and was the standard opinion in popular botanical texts such as

James Gray’s Natural Relations of British Plants of 1821, in which “race” is dened

as either “primitive” (plantae primigeniae)—“Species originally created, and not

formed by crossing with others”—or as “mule” (hybridae):

(^252) Nelson and Platnick 1981.
(^253) Croizat 1945, Lawrence 1963, Staeu 1963.
(^254) Cain 1995. Stresemann 1975, 52 notes that Linnaeus is also attempting a kind of “natural” sys-
tem even in his “articial” system, and contrasts it to the prior “classical” system—that is, the
Aristotelian system of differentiating by general features such as, in the case of birds, land or water
based lifestyles. As we saw, Bonnet retains a large amount of the classical a priorism of the mediev-
als in this respect.
(^255) Winsor 2001. For more recent discussions, see Khalidi 2009, Gill 2011, Müller-Wille 2011, Pedroso
2013, Clark 2015.
(^256) Cain 1958.
(^257) Atran 1990, 85.