Species

Species and the Birth of Modern Science 65

pressed so that exact identication of plants could be made. He inuenced a number
of his contemporaries, including Gesner, Brunfels, Fuchs, and Andreas Cesalpino,
who succeeded him as director of the garden. Although he did not write anything
that has survived, he is credibly the founder of empirical botany.^68
According to Lovejoy, the Florentine Andreas Cesalpino (1519–1603) was an
enthusiast of Aristotelian classication, and Lovejoy notes that it was the fresh study
of Aristotelian writings that set Cesalpino to producing his De Plantis (1583).^69 In
this and his Peripatetic Problems of 1588, under the Latin title Quaestionum peripa-
teticarum, libri V,^70 he worked on strict Aristotelian lines: “exhaustive comparative
analysis of the forms, concisely worded theoretical denitions, and, based on these,
abstract conclusions.”^71 Sachs quotes him saying in chapter 13:

That according to the law of nature like always produces like and that which is of the

same species with itself.^72

In chapter 14, Cesalpino stated:

We seek similarities and dissimilarities of form, in which the essence (‘substantia’) of plants

consists, but not of things which are merely accidents of them (‘quae accidunt ipsis’).^73

Cesalpino therefore seems to be a mediate source of both the idea that species are
xed, and that species have an underlying essence, or substance in the Latin, that is
distinct from other characters that may vary accidentally, which was the standard view
in medieval logical writings. Whether this meant that he was a xist, though, is open
to doubt. Cesalpino, like all those of the time, was concerned to differentiate genera
et species in De plantis, by identifying the botanical characters (differentiae) and he
uses the fructication of the plants as his basis.^74 He says in the Preface to De plantis:

Since science consists in grouping together of like and the distinction of unlike things,

and since this amounts to the division into genera and species, that is, into classes

based on characters (differentiae) which describe the fundamental nature of the things

classied, I have tried to do this in my general history of plants, ...^75

He specically names Theophrastus as the authority for this methodology.

(^68) Morton 1981, 121–124.
(^69) Arber 1938, 142f, notes that Linnaeus’ personal copy of De plantis is heavily annotated. She notes:
(^) Cesalpino’s strength lay in the fact that he approached his subject with a trained mind; he
had learned the lesson which Greek thought had then, and has now, to offer to the scientic
worker—the lesson of how to think.
(^70) Nordenskiöld 1929, 113.
(^71) Nordenskiöld 1929, 192.
(^72) Sachs 1890, 52.
(^73) Quoted in loc. cit.
(^74) Morton 1981, 135–140:
(^) Cum igitur scientia omnis in similium collectione & dissimilium distinctione consistat, hæc
autem distributio est in genera & species veluti classes secundum differentias rei naturam indi-
cantes, conatus sum id prestare in universa plantarum historia. [Caesalpini 1583, Book I, vii]
(^75) Translated in Morton 1981, 135.