Linnaeus on species

Since Linnaeus' birthday is tomorrow, my time, and I stuffed up the last post, here's another little treat for you:

Carl Linnaeus (1707–1770, from 1761 Carl von Linné, or Carolus Linnaeus)

There are many myths about Linnaeus that are due to the properties, real or imagined, of the system named after him (Cain 1994; Koerner 1999; Larson 1968; Winsor 2006). In fact the so-called "Natural System" as it came to be known, was on Linnaeus' own view an artificial one (Cain 1995), and it did not spring forth fully formed from his brow, no matter how much he saw himself as a "second Adam". His view on species was initially fairly standard, based on John Ray's previous definition (perhaps not consciously), and which included fixity. But not, it seems, because of essentialism, but piety.

Linnaeus seems to have defined each species diagnostically, not materially. That is to say, given that species are fixed from the creation, what are the marks of species so we can recognise them? However, he famously discovered what he thought was a novel hybrid species, and so towards the end of his life, began to backpedal the extreme fixity of the earlier writings, calling one such apparent novel species a "daughter of time" (Gustafsson 1979). This was widely known among the botanical community, and was widely accepted. For him, constancy (not essence) of generation was the key to species.

Below the fold are his definitions of "species", or rather, his comments about species. So far as I know, he never actually defined the term.

There are as many species as the Infinite Being produced diverse forms in the beginning. [Species tot sunt diversae quot diversas formas ab initio creavit infinitum Ens, Fundamenta botanica No. 157, 1736 (quoted in Ramsbottom 1938:196)]

We reckon as many species as there were diverse forms created in the beginning. [Species tot numeramus, quot diversae formae in principio sunt creatae, Philosophia Botanica, 1751 (loc. cit.)]

Species are as many as there were diverse [and constant*] forms produced by the Infinite Being; which forms according to the appointed laws of generation, produced more individuals but always like themselves. Therefore there are as many species as there are different forms or structures occurring today. [Species tot sunt, quot diversas [& constantes*] formas ab initio producit Infinitum Ens; quae formae, secundum generationis inditas leges, produxere plures, at sibi semper similes. Ergo species tot sunt, quot diversae formae s. structurea hodienum occurrant. Classes Plantarum, 1738 (loc.cit.). *Added in 1764, see Genera Plantarum I: ¶5]

The principle being accepted that all species of one genus have arisen from one mother through different fathers, it must be assumed:

1. That in the beginning the Creator created each natural order only with one plant with reproductive power.

2. That by their various mixings different plants have arisen which belong to the mother's natural order as they are similar to the mother with regard to their fructifications, and are, as it were, species of the order, i.e., genera.

3. We may assume that plants have arisen within the orders, i.e. by genera of one order, may mix with each other. In this way there will arise species that should be referred to the mother's genus as her daughters. [Pralectiones (Lectures, 1744), quoted in Larson, (1967:317)]

We say there are as many genera as there are similarly constituted fructifications of different natural species. [Genera tot dicimus, quot similes contructae fructifications proferunt diversae Species naturales. Fundamenta Botanica 1736, No 159 (quoted in Ramsbottom 1938:197)]

Every genus is natural, created as such in the beginning, hence not to be rashly split up or stuck together by whim or according to anyone's theory. [Genus omne est naturale, in primordio tale creatum, hinc pro libitu & secundem cujuscimque theoriam non proterve discindendum aut conglutinandum. Systema naturae, 1735, (quoted in Ramsbottom 1938:197)]

Species are most constant, since their generation is a true continuation. [Species constantissimae sunt, cum earum generatio est vera continuatio. Systema naturae, 1735 (quoted in Ramsbottom 1938:197)]

There are as many varieties as there are different plants, produced from the seed of the same species. [Varietates tot sunt, quot differentes plantae ex ejusdem speciei semine sunt productae. Philosophia Botanica 1751(quoted in Ramsbottom 1938:199)]

Is the plant [Thalictrum lucidum] sufficiently distinct from T. flavum? It seems to me a daughter of time. [Planta, an satis distincta, a T. flavo? Videtur temporis filia. Species plantarum 1753 (quoted in Ramsbottom 1938:201)]


Cain, A. J. 1995. Linnaeus's natural and artificial arrangements of plants. Botanical Journal of the Linnean Society 117 (2):73.

Cain, Arthur J. 1994. Numerus, figura, proportio, situs: Linnaeus's definitory attributes. Archives of Natural History 21:17-36.

Gustafsson, Ö. 1979. Linnaeus' Peloria: The history of a monster. TAG Theoretical and Applied Genetics 54 (6):241-248.

Koerner, Lisbet. 1999. Linnaeus: nature and nation. Cambridge, Mass: Harvard University Press.

Larson, James L. 1967. Linnaeus and the Natural Method. Isis 58 (3):304-320.

———. 1968. The Species Concept of Linnaeus. Isis 59 (3):291-299.

Ramsbottom, John. 1938. Linnaeus and the species concept. Proceedings of the Linnean Society of London 150 (192-220).

Winsor, Mary P. 2006. Linnaeus' biology was not essentialist. Annals of the Missouri Botanical Garden 93 (1):2–7.

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Thanks for the exposition.

As I write this Uppsala (Linneaus and mine alma mater) is visited by the King (Carl XVI Gustaf, Carl Gustaf) and by his guest His Imperial Majesty the Emperor (Heisei, Akihito). The dudes are going to party at Uppsala castle.

By Torbjörn Larsson, OM (not verified) on 23 May 2007 #permalink

That Cark von Linne never defined the term "species" is shocking. Clearly he struggled with the concept his entire life, but without an explanatory framework to justify the existence of species it seems hard to come up with any definition that is actually useful and respectful of observed reality. I would say a species is a group of organisms which share a gene pool, but this implies that no one organism can ever completely represent its species and that a species is inherently dynamic. How ready were they for these ideas in the 18th century?

That Cark von Linne never defined the term "species" is shocking.

But, as you touch, a descriptive empiricism have trouble. It is actually a bit surprising when it can initiate explanatory science as Linnaeus (sorry about my earlier misspelling) did.

By Torbjörn Larsson, OM (not verified) on 25 May 2007 #permalink

Linnaeus didn't need to define species, because (i) there was a popular notion amongst both folk and naturalists alike about what it was, and anyway (ii) Ray had defined it thus in 1686:

In order that an inventory of plants may be begun and a classification of them correctly established, we must try to discover criteria of some sort for distinguishing what are called "species". After long and considerable investigation, no surer criterion for determining species has occurred to me than the distinguishing features that perpetuate themselves in propagation from seed. Thus, no matter what variations occur in the individuals or the species, if they spring from the seed of one and the same plant, they are accidental variations and not such as to distinguish a species � Animals likewise that differ specifically preserve their distinct species permanently; one species never springs from the seed of another nor vice versa.

And what is more, this definition reflected the views of all naturalists back to Aristotle. Similarity plus reproductive power equals species. Nothing about fixity or essences.

As Linnaeus inherits Ray's fixity doctrine, he also inherits Ray's definition, which is the common definition of the era.