Philolaus (; Φιλόλαος , Philólaos; ) was a Greek Pythagorean and pre-Socratic philosopher. He argued that at the foundation of everything is the part played by the limiting and limitless, which combine together in a harmony. He is also credited with originating the theory that the Earth was not the center of the Universe. According to August Böckh (1819), who cites Nicomachus, Philolaus was the successor of Pythagoras.


Philolaus is variously reported as being born in either Croton, or Tarentum, or Metapontum—all part of Magna Graecia (the name of the coastal areas of Southern Italy on the Tarentine Gulf that were extensively colonized by Greek settlers). It is most likely that he came from Croton. He may have fled the second burning of the Pythagorean meeting-place around 454 BC, after which he migrated to Greece. According to Plato's Phaedo, he was the instructor of Simmias and Cebes at Thebes, around the time the Phaedo takes place, in 399 BC. This would make him a contemporary of Socrates, and agrees with the statement that Philolaus and Democritus were contemporaries.

The various reports about his life are scattered among the writings of much later writers and are of dubious value in reconstructing his life. He apparently lived for some time at Heraclea, where he was the pupil of Aresas (maybe Oresas), or (as Plutarch calls him) Arcesus. Diogenes Laërtius is the only authority for the claim that Plato, shortly after the death of Socrates, traveled to Italy where he met with Philolaus and Eurytus. The pupils of Philolaus were said to have included Xenophilus, Phanto, Echecrates, Diocles, and Polymnastus. As to his death, Diogenes Laërtius reports a dubious story that Philolaus was put to death at Croton on account of being suspected of wanting to be the tyrant; a story which Laërtius even took the trouble to put into verse.


Diogenes Laërtius speaks of Philolaus composing one book, but elsewhere he speaks of three books, as do Aulus Gellius and Iamblichus. It might have been one treatise divided into three books. Plato is said to have procured a copy of his book from which, it was later claimed, Plato composed much of his Timaeus. One of the works of Philolaus was called On Nature, which seems to be the same work which Stobaeus calls On the World, and from which he has preserved a series of passages. Other writers refer to a work entitled Bacchae, which may have been another name for the same work, and which may originate from Arignote. However, it has been mentioned that Proclus describes the Bacchae as a book for teaching theology by means of mathematics.

According to Charles Peter Mason in Sir William Smith's Dictionary of Greek and Roman Biography and Mythology (1870, p. 305):Additionally Charles Peter Mason noted (p. 304):Historians from the Stanford Encyclopedia of Philosophy, Chapter Philolaus' Book: Genuine Fragments and Testimonia), noted the following:


The book by Philolaus begins with the following:Robert Scoon explained Philolaus universe in 1922:

Stobaeus account

Philolaus did away with the ideas of fixed direction in space, and developed one of the first non-geocentric views of the universe. His new way of thinking quite literally revolved around a hypothetical astronomical object he called the Central Fire.In Philolaus's system a sphere of the fixed stars, the five planets, the Sun, Moon and Earth, all moved round his Central Fire. According to Aristotle writing in Metaphysics, Philolaus added a tenth unseen body, he called Counter-Earth, as without it there would be only nine revolving bodies, and the Pythagorean number theory required a tenth. However, according to Greek scholar George Burch, Aristotle was lampooning Philolaus's ideas. In reality, Philolaus' ideas predated the idea of spheres by hundreds of years. Nearly two-thousand years later Nicolaus Copernicus would mention in De revolutionibus that Philolaus already knew about the Earth's revolution around a central fire.

However, it has been pointed out that Stobaeus betrays a tendency to confound the dogmas of the early Ionian philosophers, and he occasionally mixes up Platonism with Pythagoreanism.


Philolaus argued at the foundation of everything is the part played by the ideas of limit and the unlimited. One of the first declarations in the work of Philolaus was that all things in the universe result from a combination of the unlimited and the limiting; for if all things had been unlimited, nothing could have been the object of knowledge. Limiters and unlimiteds are combined together in a harmony (harmonia):