Theophrastus

Theophrastus of Eresos (c. 371 to c. 287 BC) was an ancient Greek philosopher and naturalist, a pupil of Plato and close colleague of Aristotle, whom he succeeded as head of the Lyceum. Born on the island of Lesbos, he is remembered above all as a developer of the Aristotelian system and, for his work on plants, as the father of botany. His birth name was Tyrtamus. The nickname Theophrastus, roughly meaning divine speaker, is said to have been given to him by Aristotle in praise of his eloquence.

According to the tradition preserved by Diogenes Laertius, he received his first introduction to philosophy on Lesbos from a certain Alcippus, then moved to Athens, where he probably studied under Plato. After Plato's death he attached himself to Aristotle, and he very likely joined him on Lesbos, where the two are thought to have begun their studies of nature: Aristotle concentrating on animals, Theophrastus on plants. He later followed Aristotle to Macedonia and returned with him to Athens around 335 BC. When Aristotle left the city, Theophrastus took charge of the Lyceum. Aristotle left him his library, the originals of his writings and the guardianship of his children.

For more than thirty years he led the Peripatetic school, which according to ancient reports grew to more than two thousand students at one point. The comic poet Menander was among them. His output was enormous: ancient catalogues list around two hundred titles, though most have been lost. His two large botanical treatises, Enquiry into Plants and On the Causes of Plants, were the most important contribution to botany in antiquity and the Middle Ages. In them he grouped plants by their mode of generation, their habitats, their size and their uses. He also wrote on physics, metaphysics, logic, ethics and politics. In ethics and in some metaphysical questions, such as motion, the soul and God, he departed from Aristotle, though much of his thought survives only in fragments and in later commentators.

His best-known work outside specialist circles is The Characters, a short, sharp collection of moral portraits that is regarded as the first systematic attempt to describe types of human character and that inspired later writers such as Jean de La Bruyère. His influence on Renaissance science was considerable; Linnaeus called him the father of botany. He died at about the age of eighty-five, and the Athenians gave him a public funeral.