Pythagore de Samos
All is number.
Pythagore de Samos (VIe s. av. J.-C., Samos (Ionia), then Croton (southern Italy)) : presocratics. Pythagoras is a name surrounded by legend. Tradition gives him two ideas: the soul passes from one body to another, and numbers govern the order of the world. On AskPhilosophy: 2 reconstructed arguments, 2 quotes checked word for word against the original texts, and 4 common beliefs examined; every text carries an authenticity badge (written by the author, posthumous, student notes, reported, apocryphal).
What do we really know about him?
Very little. Even his dates are uncertain: ancient sources have him born c. 580-570 and dying c. 495-490 BC; our timeline uses 582-490, dates often quoted but no surer than the others. The oldest witnesses are his contemporaries: Xenophanes (verses) and Heraclitus (a prose sentence), c. 500 BC, whom we read only as quoted much later by Diogenes Laertius (c. 230 AD, about seven centuries after him). Herodotus (c. 430 BC) calls him "not the weakest of the Greek sages". Aristotle (c. 340 BC, about 150 years after) writes about "the Pythagoreans" and hardly ever names the master. Diogenes Laertius' Life mixes legend, accounts of doctrine and a letter whose authenticity is doubtful. On this site every excerpt carries the badge "transmitted by others" and names who reports it.
Pythagoras or the Pythagoreans?
When Aristotle says that "all things are numbers", he writes "the Pythagoreans" or "the so-called Pythagoreans", and never "Pythagoras". We do not know what belongs to the master and what to his disciples, such as Philolaus, who according to Diogenes Laertius published the school's first books. That is why the argument about numbers is presented here as the Pythagoreans'.
A shorter page than the others
We do not fill in the radar axes: no certain text by Pythagoras tells us whether he believed in God, what we can know, or whether the mind is matter. Each axis is left empty and explains why. None of our questions asks "what is the world made of?": the argument about numbers is filed where it fits least badly (see the argument's page).
His positions
click a row to see the evidenceDiogenes Laertius reports, from Aristotle, that Pythagoras worshipped only at the altar of Apollo the Begetter at Delos, where only wheat, barley and cakes were laid, without fire or victim. It is a reported practice, not a doctrine on God's existence. We do not score this axis.
Two testimonies point in opposite directions. Heraclitus (c. 500 BC, authenticity of the fragment debated) says Pythagoras "practised inquiry beyond all other men", so rather experience and learning. Aristotle says the Pythagoreans started from mathematics, so rather reason. The second speaks of the disciples, the first mocks. We do not score this axis.
Aristotle credits the Pythagoreans with the conviction that numbers hold the key to all of nature. This touches certainty, but it is a doctrine of the Pythagoreans reported by Aristotle, not a text by Pythagoras on what we can know. We do not score this axis.
Diogenes Laertius cites "Pythagorean memoirs" (Alexander Polyhistor, 1st c. BC, about four and a half centuries after Pythagoras): the soul has three parts, and reason is immortal, the rest mortal. Authenticity doubtful, and the question materialism or dualism is not asked there. We do not score this axis.
The same "Pythagorean memoirs" say that the most important thing in human life is to push one's soul towards good or evil. One may read a free choice into it, but the text is late and does not discuss necessity. We do not score this axis.
The reported precepts say nothing about whether good is objective. We do not score this axis.
Nothing says how Pythagoras understood the relation between believing and reasoning. The accounts of his earlier lives are given as facts to believe, with a "test" (the shield), but the account is late and legendary. We do not score this axis.
The idea that the soul passes from body to body could give meaning to life, but no certain testimony says so. We do not score this axis.
No certain testimony about human nature. The "Pythagorean memoirs" speak of the soul and its choice between good and evil, without saying whether humans are naturally good. We do not score this axis.
Diogenes Laertius writes that Pythagoras laid down laws for the Italian Greeks and that his three hundred or so disciples governed so well that the regime was "almost an aristocracy" (government by the best). It is a fact reported seven centuries later, not a theory of the individual and the community. We do not score this axis.
Diogenes Laertius reports a list of precepts (support the law, honour elders, do not kill a harmless animal, abstain from beans). These are rules of life handed down in the school, with no theory behind them: they cannot be placed under duty, consequences or virtues. We do not classify this axis.