150 ADVANCEMENT OF LEARNING 



cycles to preserve their circular rotation; tliat the moon has 

 no influence over bodies higher in the heavens ; the absurd 

 ity of which notions have thrown men upon the extravagant 

 idea of the diurnal motion of the earth, an opinion which 

 we can demonstrate to be most false. 8 But scarce any one 

 has inquired into the physical causes of the substance of the 

 heavens, stellar and interstellar; the different velocities of 

 the celestial bodies with regard to one another ; the different 

 accelerations of motion in the same planet; the sequences 

 of their motion from east to west; 9 the progressions, stations, 

 and retrogradations of the planets, the stoppage and acci 

 dents of their motion in perigee and apogee, the obliquity 

 of their motions ; why the poles of rotation are principally 

 in one quarter of the heavens; why certain planets keep a 

 fixed distance from the sun, etc. Inquiries of this kind have 

 hitherto been hardly touched upon, but the pains have been 

 chiefly bestowed in mathematical observations and demon 

 strations; which indeed may show how to account for all 

 these things ingeniously, but not how they actually are 

 in nature: how to represent the apparent motions of the 

 heavenly bodies, and machines of them, made according 

 to particular fancies ; but not the real causes and truth of 

 things. And therefore astronomy, as it now stands, loses 

 its dignity by being reckoned among the mathematical 

 arts, for it ought in justice to make the most noble part 

 of physics. I0 And whoever despises the imaginary separa- 



8 That doctrine had been recently demonstrated by Galileo, and defended by 

 Gilbert. 



9 That is, from west to east, according to the Copernican system. Ed. 



10 Bacon maps out the entire region of human knowledge, breaking up the 

 old sections, and assigning to each science new boundaries more conformable in 

 his view to strict philosophical notions than the old ; yet he capriciously enough 

 makes mathematics an essential part of metaphysics, or inquiry into forms, and 

 astronomy a compartment of mathematics, and then decries this absurd arrange 

 ment as the notion of the age. It is evident, however, that the age was inno 

 cent of the charge, and that Bacon snatched up the idea from the demonstra 

 tions which Copernicus, Kepler, and Gilbert employed to dethrone the Ptolemaic 

 theory of the heavens. Bacon was too jealous of Gilbert to entertain one moment 

 any doctrine that he advanced ; and a little further on he alludes to his mathe 

 matical thesis in favor of the earth s diurnal motion as proofs contradicted by 

 natural philosophy, though incapable of being confuted by observation. Prom 



