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CHAPTER II. 



INDUCTION OF COPERNICUS. THE HELIOCENTRIC 

 THEORY ASSERTED ON FORMAL GROUNDS. 



IT will be recollected that the formal are opposed 

 to the physical grounds of a theory; the former 

 term indicating that it gives a satisfactory account 

 of the relations of the phenomena in Space and 

 Time, that is, of the Motions themselves; while 

 the latter expression implies further that we in- 

 clude in our explanation the Causes of the motions, 

 the laws of Force and Matter. The strongest of 

 the considerations by which Copernicus was led 

 to invent and adopt his system of the universe 

 were of the former kind. He was dissatisfied, he 

 says, in his Preface addressed to the Pope, with 

 the want of symmetry in the Eccentric Theory, 

 as it prevailed in his days; and weary of the 

 uncertainty of the mathematical traditions. He 

 then sought through all the works of philosophers, 

 whether any had held opinions concerning the mo- 

 tions of the world, different from those received in 

 the established mathematical schools. He found, in 

 ancient authors, accounts of Philolaus and others, 

 who had asserted the motion of the earth. "Then," 

 he adds, " I, too, began to meditate concerning the 

 motion of the earth : and though it appeared an 



