The Europeans, no 10: Carolus Linnaeus

Carl Linnaeus developed the Latin two-word system for organising the natural world that is still in use today, writes ENDA O'DOHERTY

The botanist Carolus Linnaeus was born Carl Nilsson Linnaeus in 1707 in the southern Swedish province of Smaland. His clergyman father, Nils, taught the young Carl Latin, religion and geography before he entered formal schooling. Some perceptive teachers later noticed and encouraged his fascination with flowers, one introducing him to Smaland’s state doctor, Johan Rothman, who pushed him towards medicine (botany in this period was almost exclusively studied for its pharmacological applications rather than as a discipline in itself).

Linnaeus attended first Lund university, and then Uppsala, where he wrote a treatise on the sexual reproduction of plants. On the basis of this he was asked to give lectures, though still only a second-year student. He continued writing energetically, combining study with field trips, which themselves resulted in further books.

In 1735 he visited the Netherlands, whose scholars excelled in natural history, planning to take a doctoral degree in medicine at the University of Harderwijk. Linnaeus handed in a work he had already written on the causes of malaria, publicly defended it, took an oral examination, diagnosed a patient, and was awarded his doctorate, all within two weeks of arriving at the university.

In the following year, he visited England, meeting the keeper of the Chelsea Physic Garden, Philip Miller, and the Oxford University botanist Johann Jacob Dillenius.

In 1735, the first edition of his Systema Naturae was published. It divided the natural world into the animal, plant and mineral “kingdoms”. He was the first to systematically and consistently use binomial nomenclature to describe plants and animals, replacing the previous long and unwieldy (Latin) names with a simple two-word formula, as in primula vulgaris (the primrose) or homo sapiens (a term Linnaeus coined).

He divided the kingdoms into classes, which were in turn divided into orders, then genera (genus is the singular) and species. The classification of plants in Systema Naturae followed the “sexual system”, where species with the same number of stamens were treated as being in the same group.

Linnaeus believed that he was classifying creation rather than explaining its underlying principles. “God created, Linnaeus organised” was how he described his work.

Nevertheless, he took the controversial and perhaps even dangerous step of including humans as just another element (sharing the order Anthropomorpha, or Primates, with the apes) rather than a privileged species, made “in the image of God” to dominate nature and turn it to its own use.

It was not that Linnaeus wished to bring man down to the level of the apes, as Darwin was to be accused of doing. Indeed he had a respect for animals that strikes a quite modern note: “One should not vent one’s wrath on animals. Theology decrees that man has a soul and animals [do not], but I believe they would be better advised that animals have a soul and that the difference is of nobility [that is, of degree].”

Linnaeus’s system of classification has of course been much modified and added to over the almost 300 years since he began his work.

He was dealing with numbers of species in the tens of thousands; today we estimate 1.9 million. Yet his works, in particular the Species Plantarum (1753) and the 10th edition of the Systema Naturae (1758), are the pillars on which modern species classification (taxonomy) is built.

In his final years (he died in 1778), Linnaeus suffered several strokes and lost his memory. When brought some of the great books he had published he was able to admire their brilliance, but he no longer knew that he had written them.

What to read

Wilfrid Blunt's Linnaeus: The Compleat Naturalist, published by Frances Lincoln, offers an account of Linnaeus's scientific advances, his field trips and the important place that his students played in the later development of botany.