Greek philosophers
Hippasus of Metapontus
Hippasus of Metapontus was a Greek pre-Socratic philosopher and mathematician who lived in the 5th century BC and was born in the city of Metapontus (present-day Italy). He was a representative of Pythagoreanism.
Very little is known about the life of Hippasus of Metapontus. He is considered to be the discoverer of irrational numbers, which is said to have caused a panic in the Pythagorean brotherhood. He was eventually expelled from the brotherhood.
Hippasos considered fire to be the primordial substance, where everything is created by its condensation, thus following Aristotle. He considered the universe to be bounded and in constant motion, thus following Diogenes Laertius.
Hippasos was also to discover the basic rules of music theory. This fact was asserted by Plato.