Aristotle	Democritus

Ancient Greek philosophers were among the first to speculate about the nature of matter and many of them formed schools where fundamental questions of nature and morality were debated. We begin with Democritus of Abdera, who was born in Thrace in ancient Greece, and who lived from about 470BC to 380BC. Democritus held that all matter consisted of tiny particles that were so small that they could not be broken down into any smaller pieces. He coined the word `atamos' which literally means invisible. In Democritus's view, these `atoms' were physically different from each other so that "atoms of water" were smooth because water flowed and had no discernible shape. `Atoms of fire' were `thorny' which is why the fire gave you painful burns. 'Atoms of earth` were rough and jagged so that they stuck together to form hard materials.

Another influential idea was that of Empedocles (430-390BC). He combined the ideas of Thales (640-540BC) who thought that the basic element of matter was water, Anaximenes (611-546BC) who thought it was air, and Heraclitus (540-475BC) who thought it was fire. To this Empedocles added one of his own: Earth. Thus was born the notion of all matter being made out of differing amounts of fire, air, earth and water

Aristotle (384-322BC) who founded the famous school of philosophy in Athens called Lyceum, perpetuated Empedocles' view of matter right through to medieval times. Aristotle's lectures on nature were collected into many volumes in which he entirely rejected Democritus's idea of the atom. The Aristotelian world view dominated until the scientific revolution in the 16th and 17th centuries where Democritus's ideas of the atom were brought back.