1 6 HISTORY OF SCIENCE. 



Pythagorean notions were largely entertained by the philosophers of 

 the Middle Ages, and that even at the present day there are not want- 

 ing persons who occupy their minds with speculations of this kind. 

 The " music of the spheres," false as it is in science, is often appro- 

 priately enough alluded to by our poets. Thus Pope, in the " Essay 

 on Man " : 



If Nature thundered in his opening ears 

 And stunned him with the music of the spheres, 

 How would he wish that Heaven had left him still 

 The whispering zephyr and the purling rill ! 



But as the music of the spheres, notwithstanding its sweetness and 

 loudness, was inaudible to mankind, Pythagoras had to explain why 

 it was unheard. His explanation was ingenious, and indeed it indi- 

 cates a real truth as to the nature of our perceptions. The music of 

 the spheres is unheard, said Pythagoras, because it is ever and un- 

 ceasingly resounding in men's ears from the moment of their birth. It 

 is certainly true that we recognize no condition of sensation except 

 by the change from another condition, and that we could never have 

 been conscious of sound and silence except by their contrast. 



' Pythagoras had many disciples, and it is impossible to distinguish 

 the doctrines held by him from later developments of these doctrines 

 by his followers. His predecessors had arrogated to themselves 

 the title of wise men, but he first called himself a lover of* wisdom 

 (0iAo-o-o0os), and thus we have the name of philo-sophy. Pythagoras 

 never committed his doctrines to writings, and oral instruction became 

 the tradition of the school. It was also part of the Pythagorean plan 

 to veil the higher truths of their philosophy in mysterious language, 

 which was intended to be understood only by those fully initiated. 

 Their maxim was that not unto all should all things be taught, and 

 therefore on many subjects they openly professed certain doctrines 

 the exoteric while they secretly inculcated others the esoteric. It is 

 believed that among these last Pythagoras taught his disciples some- 

 thing very like the astronomy which places the sun in the centre of 

 our system, and recognizes in the fixed stars suns which are the centres 

 of other systems. Even that which filled the popular mind with terror 

 the comet, that 



from his horrid hair 

 Shakes pestilence and war, 



by the Pythagoreans could be contemplated calmly; for the philo- 

 sopher of Cretona seems to nave been aware that the comet was also 

 a body revolving about the sun, like a planet visible in only a part of 

 its orbit. 



It would appear from the 'account given of the Pythagorean doc- 

 trines by Aristotle that these philosophers had a notion of both the 

 diurnal and the annual revolutions of the earth, as well as of its ro- 

 tundity. He tells us that in the centre of the universe the Pythago- 



