PROFESSOR LOVERING'S ADDRESS. 311 



has filled up again. Nature's abhorrence of a vacuum has been resus- 

 citated, though for other reasons than those which satisfied the Aris- 

 totelians. It is the mathematicians and not the metaphysicians who 

 are now discussing the relative merits of the plenum and the vacuum. 

 Newton, in his third letter to Bentley, wrote in this wise : " That grav- 

 ity should be innate, inherent, and essential to matter, so that one 

 body may act upon another at a distance, through a vacuum, without 

 the mediation of any thing else, by and through which their action 

 and force may be conveyed from one to another, is to me so great an 

 absurdity, that I believe no man, who has in philosophical matters a 

 competent faculty of thinking, can ever fall into it." Roger Cotes, 

 who was Newton's successor in the chair of Mathematics and Natural 

 Philosophy at Cambridge, was only four years old when the first 

 edition of the "Principia" was issued, and Newton outlived him by 

 ten years. The venerable teacher pronounced upon the young mathe- 

 matician, his pupil, these few but comprehensive words of eulogy : 

 " If Cotes had lived, we should have known something." The view 

 taken of gravitation by Cotes was not the same as that held by his 

 master. He advocated the proposition that action at a distance must 

 be accepted as one of the primary qualities of matter, admitting of no 

 further analysis. It was objected by Hobbes and other metaphysi- 

 cians, that it t was inconceivable that a body should act where it was 

 not. All our knowledge of mechanical forces is derived from the con- 

 scious effort we ourselves make in producing motion. As this motion 

 employs the machinery of contact, the force of gravitation is wholly 

 outside of all our experience. The advocates of action at a distance 

 reply that there is no real contact in any case, that the difficulty is 

 the same with the distance of molecules as that of planets, that the 

 mathematics are neither long-sighted nor short-sighted, and that an 

 explanation which suits other forces is good enough for gravitation. 



Comte extricated himself from this embarrassment by excluding 

 causes altogether from his positive philosophy. He rejects the word 

 attraction as implying a false analogy, inconsistent with Newton's law 

 of distance. He substitutes the word gravitation, but only as a blind 

 expression by which the facts are generalized. According to Comte's 

 philosophy, the laws of Newton are on an equality with the laws of 

 Kepler, only they are more comprehensive, and the glory of Kepler 

 has the same stamp as that of Newton. Hegel, the eminent German 

 metaphysician, must have looked at the subject in the same light when 

 he wrote these words : " Kepler discovered the laws of free motion ; a 

 discovery of immortal glory. It has since been the fashion to say that 

 Newton first found out the truth of these rules. It has seldom hap- 

 pened that the honor of the first discoverer has been more unjustly 

 transferred to another." Schelling goes further in the same direction : 

 he degrades the Newtonian law of attraction into an empirical fact, 

 and exalts the laws of Kepler into necessary results of our ideas. 



