THE GOLDEN AGE OF GREECE 81 



refraction mathematically. While he undertakes to deal with 

 motion, space and time i.e. with the subject-matter of me- 

 chanics his treatment is too metaphysical to have much real 

 value. He declares for example that : - 



The bodies of which the world is composed are solids, and 

 therefore have three dimensions. Now, three is the most per- 

 fect number, it is the first of numbers, for of one we do not speak 

 as a number, of two we say both, three is the first number of 

 which we say all. Moreover, it has a beginning, a middle, and an 

 end. 



Francis Bacon in the seventeenth century remarks of 

 Aristotle : 



Nor let any one be moved by this ; that in his books Of Animals, 

 and in his Problems and in others of his tracts, there is often a quoting 

 of experiments. For he had made up his mind beforehand; and 

 did not consult experience in order to make right propositions and 

 axioms, but when he had settled his system to his will, he twisted ex- 

 perience round, and made her bend to his system ; so that in this way 

 he is even more wrong than his modern followers, the Schoolmen, who 

 have deserted experience altogether. 



ARISTOTELIAN ASTRONOMY. Only the second of the four 

 books on the Heavens is devoted to astronomy. He considers the 

 universe to be spherical, the sphere being the most perfect among 

 solid bodies, and the only body which can revolve in its own space. 

 Rotation from east to west is more honorable than the reverse. 

 He holds that the stars are spherical in form, that they have no 

 individual motion, being merely carried all together by their 

 one sphere. 



' Furthermore, since the stars are spherical, as others maintain and 

 we also grant, because we let the stars be produced from that body, 

 and since there are two motions of a spherical body, rolling along and 

 whirling, then the stars, if they had a motion of their own, ought to 

 move in one of these ways. But it appears that they move in 

 neither of these ways. For if they whirled (rotated), they would re- 

 main at the same spot and not alter their position, and yet they 

 manifestly do so, and everybody says they do. It would also be 



