Definition: Philolaus was a Pythagorean philosopher
(c.470 - c.385)
from Croton in Southern Italy, where Pythagoras had migrated. Philolaus was
a contemporary of Socrates and probably the first Pythagorean to have written a book (On Nature). Philolaus is noteworthy for determining that the earth is a planet; however, for him it circled the central fire, rather than the sun. It was Philolaus' book that Aristotle used to describe the Pythagoreans. Plato also used Philolaus' writing in his Phaedo.
More than 20 fragments attributed to Philolaus survive.
Philolaus argues that the universe is made of two things, limiters and unlimiteds. The unlimited are undefined and include earth, air, fire, water, space, and time. Limiters can be structures like shape. Unlimiteds and limiters fit together harmonically or mathematically. A musical scale is an example where the sound is limited by ratios.
Source:
Huffman, Carl, "Philolaus", The Stanford Encyclopedia of Philosophy (Fall 2003 Edition), Edward N. Zalta (ed.).
