Democritus came from Abdera, a city in Thrace. He lived c. 460–380, a generation later than two other philosophers from Abdera, Protagoras (below, p. 173) and Leucippus. Democritus and Leucippus are known as the inventors of atomism, the theory that all matter consists of atoms and void. In addition to fragments on physics, more than a hundred ethical/political fragments are attributed to Democritus. Although their authenticity has been doubted, a majority of scholars accept them as authentic. We present here only those fragments that deal with the themes of this volume.

(DK 5)

This is an excerpt from the History of Diodorus Siculus (1.8) who wrote in the first century. It does not mention Democritus, but is based on the work of a fifth-century thinker, and this is likely to have been Democritus (see Cole, Bibliographical Note, § B.4).

The generations of humans born in the beginning led an unruly and bestial life. They foraged individually for food and consumed the most pleasing of the plants and whatever fruit fell from the trees. When attacked by wild beasts, they helped each other, learning that this was mutually advantageous; and when they were thus brought together by fear, little by little they learned each other's ways. The sounds of their voices were confused and unintelligible at first, but gradually they articulated words, and by establishing signs (symbola) for each existing thing, they taught each other the meanings of each of them.