Born in Clazomene,
Asia, Anaximander was the first philosopher to settle in Athens where he founded
a school. There he was to teach for 30 years, but after upsetting the Athenians
We do not have much of Anaxagoras' work, but we know that he wrote a book on nature, Peri Physeos ("On Nature"). There he explained that all matter originally exists as atoms or molecules, tiny units that had always existed.
He was the first to introduce the idea of nous ("mind or reason"). Where the previous philosophers had been interested in the four elements, Anaxagoras thought that the nous had organised the chaotic atoms and thus creating order. These ideas were to inspire both Aristotle and Democritus.