The Pythagorean Question, Stated Plainly

Almost nothing about the historical Pythagoras can be established with real confidence, and the reasons are structural rather than accidental. Pythagoras himself wrote nothing that survives, and very likely wrote nothing at all. The earliest references to him, from writers close to his own time, are brief and several are openly hostile, offering fragments of caricature rather than description. The full, richly detailed portraits familiar today, crediting Pythagoras with major mathematical discoveries, reports of miracles and a status bordering on the divine, were composed by Neoplatonist authors writing centuries after his death, working within their own philosophical and religious agendas and drawing on a legendary tradition that had grown considerably in the intervening centuries. Scholars call this evidentiary gap the Pythagorean question, and it means that nearly every specific claim commonly repeated about Pythagoras personally, as opposed to about the school and tradition that carried his name forward, has to be weighed against the possibility that it belongs to a later stage of legend building rather than to the man himself. The difficulty is not that sources disagree about details; it is that the earliest reliable sources say almost nothing at all.