Species

Species and the Birth of Modern Science 89

only that there should be no a priori specication of what characters were to be used,

contrary to Linnaeus.^186 He noted that

[w]hat is sufcient to constitute the genera of certain families is not sufcient for other

families, and neither the same parts nor the same number of these parts invariably

furnish these [constituent] parts in each family.^187

Although he was primarily concerned with higher taxa than the species level, he

did give a denition of species in the second part of the Preface to the Familles des

plantes. A denition of species founded only on sexual reproduction fails to apply

for all organisms, but applies only for some plants, and most animals. So, such a

denition is articial and arbitrary, and if all possibilities are considered, the term

becomes hard to dene.

Although it is very difcult, not to say impossible, to give an absolute and general

denition of any object of natural history whatever, one could say rather exactly that

there are as many species as there are different individuals among them, different in

any (one or more) respect, constant or not, provided they are denitely perceptible

and taken from parts or qualities where those differences appear to be most naturally

placed in accordance with the particular character of each family.^188

He rejected the denition of Buffon, in part because he wanted still to include min-
eral species under the rubric,^189 but also because he recognized the existence of asex-
ual plants and even some animals. He notes that although there may be, as Buffon had
said, only individuals in nature, and that for God all is one, for us it is divided, and “et
cela sufit” (and that sufces), the differences are real even if to divine inspection the
species are not. He does think, though, that there is continuity in nature, and that we
see gaps between species only because some have become extinct. In a handwritten
denition in the fth volume of his copy of the Encyclopédie of Diderot,^190 he wrote:

Species: collection of all objects which nature separates individually from each other

as so many isolated entities existing separately and which the imagination or the free

and creative opinion of man unites idéalement each time that he nds an almost com-

plete resemblance or a resemblance at any rate greater than with any other group, a

collection to which he gives the name species.^191

(^186) Staeu 1963, 184.
(^187) Morton 1981, 305.
(^188) Translation from Staeu 1963, 185. The French is:
(^) Denition de l’Espèce.
(^) Ainsi, quoiqu’il soit très-dicil, pour ne pas dire impossible, de donor une dénition absolue
& générale d’aucun objet de l’Hist. nat. on pouroit dire assez exactemant qu’il existe autaunt
d’Espèces, qu’il i a d’Individus diférans entreaux, d’une ou de plusieurs diférances quelkonkes,
constantes ou non, pourvu qu’eles soient très-sensibles, & tirées des parties ou qualités où ces
diférances paroissent plus naturelement placées, selon le génie ou les moeurs propres à chaque
Famille; ... [Adanson 1763, clxviij]
(^189) Staeu 1963, 182f. The notion that minerals “grew” in the earth was still current at this time.
(^190) Diderot himself was a transmutationist of the Great Chain variety. See Gregory 2007.
(^191) Translated in Staeu 1963, 186.