PLATO

 

The Greek philosopher Plato (428–348 BCE) was born just a year after the infamous plague. He was not a mathematician, but he believed that mathematics was the study of truth. To emphasize this view, Plato placed a sign over the gate of his Academy in Athens: LET NO ONE IGNORANT OF GEOMETRY ENTER HERE! Plato thus became known as the maker of mathematicians, and he encouraged many geometers and algebraists to join what would later be considered the first center of philosophy and knowledge in the world.

Mathematicians of ancient Greece knew that there were five, and only five, regular solids. These are three-dimensional geometrical objects whose faces are all identical to one another. The solids that satisfy this requirement are the cube, the tetrahedron (triangle-based pyramid), the octahedron, the icosahedron, and the dodecahedron. Plato admired the discovery and ascribed much importance to these solids; so they became known as the Platonic solids. The Greeks associated the five solids with elements of nature: earth, water, air, and fire, as in the figure.

Of the five solids, Plato considered the dodecahedron so important that he named it the “fifth essence,” or quintessence, from which we get the word quintessential.