290 HISTORY OF FORMAL ASTRONOMY. 



force which modern philosophy has established, is in the direction of 

 the radius, and nearly perpendicular to the body's path. Kepler was 

 right no further than in his suspicion of a connection between the cause 

 of motion and the distance from the centre ; not only was his knowl- 

 edge imperfect in all particulars, but his most general conception of 

 the mode of action of a cause of motion was erroneous. 



With these general convictions and these physical notions in his 

 mind, Kepler endeavored to detect numerical and geometrical relations 

 among the parts of the solar system. After extraordinary labor, per- 

 severance, and ingenuity, he was eminently successful in discovering 

 such relations ; but the glory and merit of interpreting them according 

 to their physical meaning, was reserved for his greater successor, 

 Newton. 



CHAPTER IV. 

 INDUCTIVE EPOCH OF KEPLER. 



Sect. 1. Intellectual Character of Kepler. 



QEVERAL persons, 1 especially in recent times, who have taken a 

 ^ view of the discoveries of Kepler, appear to have been surprised 

 and somewhat discontented that conjectures, apparently so fanciful and 

 arbitrary as his, should have led to important discoveries. They seem 

 to have been alarmed at the Moral that their readers might draw, 

 from the tale of a Quest of Knowledge, in which the Hero, though fan- 

 tastical and self-willed, and violating in his conduct, as they conceived, 

 all right rule and sound philosophy, is rewarded with the most signal 

 triumphs. Perhaps one or two reflections may in some measure rec- 

 oncile us to this result. 



i Laplace, Precis de VHist. <PAst. p. 94. "II est affligeant pour 1'esprit humain 

 de voir ce grand liomme, meme dans ses dcrniers ouvrages, se coinplaire avec de- 

 lices dans ses chimeriques speculations, et les regarder comme 1'dme et la vie de 

 rastronomie." 



Hist. ofAst., L. U. K., p. 53. " This success [of Kepler] may well inspire wilu 

 dismay those who are accustomed to consider experiment and rigorous induction 

 as the only means to interrogate nature with success." 



Life of Kepler, L. IT. K., p. 14, " Bad philosophy." P. 15, " Kepler's miraculous 

 good fortune in seizing truths across the wildest and most absurd theories." P 

 54, " The danger of attempting to follow his method in the purs-jit of truth." 





