​SPHERES, MUSIC OF THE, in Pythagorean philosophy, the harmony produced by the heavenly bodies in their orbits, inaudible to human ears. Pythagoras (cf. Arist. de Caelo, ii. 9) held that the movements of stars were governed by fixed laws which could be expressed in numbers according to the numbers which give the harmony of sounds (see , ad fin.). It is this theory to which Shakespeare alludes in The Merchant of Venice (Act. v. i. seq.: "such harmony is in immortal souls, but. .. we cannot hear it"). According to Gomperz (Greek Thinkers, i. 118, Eng. trans.) "there was nothing fanciful in the Pythagorean doctrine except only the belief that the differences of velocity in the movements of the stars were capable of producing a harmonious orchestration and not merely sounds of varying pitch."