Note 260 — Chapter I

Pythagoras has left no writings; Aristotle speaks only of his school; Diogenes Laertius in one passage (Vitae, viii. 1 (Pythag.), 25) quotes an authority to the effect that Pythagoras asserted the earth to be spherical and inhabited all over, so that there were antipodes, to whom that is over which to us is under. As all his disciples agreed on the spherical form of the earth while differing as to its position and motion, it is probable that they took the idea of its form from him. Diogenes Laertius states that Parmenides called the earth round (στρογγύλη, viii. 48), and also that he spoke of it as spherical (σφαιροειδῆ, ix. 3); the passages are not, as has been sometimes assumed, contradictory. The enunciation of the doctrine is often attributed to Thales and to Anaximander, on the authority of Plutarch, De placitis philosophorum, iii. 10, and Diogenes Laertius, ii. 1, respectively; but the evidence is conflicting (Simplicius, Ad Aristot., p. 506b. ed. Brandis; Aristot., De caelo, ii. 13; Plutarch, De plac. phil. iii., xv. 9).