THE NEWTONIAN PHILOSOPHY. 541 



a caiife, when any caufe is made to operate beyond its power or efR- 

 cacy, the thing fuppofed to be produced muft be without a caufe. 



2do^ It is admitted that, in this cafe, the motion is retarded, and, at 

 laft, ceafes altogether, by the refiftence of the medium. It is therefore 

 confeffed not to be, in every'refped, eternal ; and, if it is put an end 

 to in one way, why not in another ? why not in the way that all 

 mortal things end, by gradual decay, and, at laft, death ? The a£livc 

 principle, therefore, which moves body for fome time, grows weaker 

 and weaker by degrees, like the animal life when it draws to an end, 

 and, at laft, like it, ceafes altogether ; for we are not to underftand, 

 as the Newtonians do, in arguing upon this fubjedl, that the body 

 flops itfelf : This, indeed, would be giving adivity to body. But I 

 fay that the adive principle which is in the body, and is quite dif- 

 tin<5t from the body, ceafes to exert itfelf. 



2,tio^ In a queftion of this kind, which cannot be determined by ex- 

 perimeni, even thofe philofophers who would confine all our know- 

 ledge of nature to fads and experinients, muft, 1 think, allow that the 

 argument from final caufes deferves fome attention. Now, it is abfo- 

 lutely necefTary for carrying on the bufinefs of nature here below, that 

 there fhould be motion by bodily impulfe, in the way of pulfion as. 

 well as of trufion ; but there can be no reafon given why this motion 

 fhould be eternal ; and, therefore, as Nature does nothing in vain, 

 we cannot fuppofe it to be eternal. 



Lajlly^ Nature, according to Ariftotle, is a principle of reft, as well 

 as of motion : And, accordingly, we fee that bodies have determinate 

 motions to certain places, and for certain ends, which when they have 

 attained, they ceafe to be moved. Thus, heavy bodies are moved to- 

 wards the center of our earth ; and, if they were to arrive at that cen- 

 ter, 



