8 ANTIENT METAPHYSICS. Book I. 



For thefe are all the caufes by which motion can be produced. 

 And I will only add, that the two caufes laft mentioned operate 

 in very different manners : For body moves body only by an 

 external application to it, either impelling or drawing it, whereas 

 mind moves body by adting,upon it internally. 



I will begin with the fimpleft of thefe caufes, that is Body mov- 

 ing itfelf ; and which, according to the philofophy of Sir Ifaac New- 

 ton, is the caufe of body, once put in motion, continuing in motion : 

 For he fays, it continues to move (or, to fpeak more properly, to be 

 moved) in a ftraight line and with an uniform velocity, by a vis in- 

 fita^ that is by a power inherent in the matter and eflential to it. 

 This he has laid down in his third definition, in his work, entit- 

 led, Prhicipia Mathematica Fhilofophiae Natiiralis ; and he has alfo 

 laid it down as an axiom, calling it the firft law of motion. 



Sir Ifaac, in this definition and axiom, has faid nothing of the be- 

 ginning of motion ; but only fpeaks of the continuance of it after it is 

 begun. But for my part I can make no diftindlion betwixt the two : 

 for motion is ftill motion and the fame motion whether beginning 

 or going on ; and when the iron, brought withia a certain diftance of 

 the loadllone, begins to be moved towards it, that motion muft be by 

 a vts Infita too, as well as the continuation of the motion of body 

 after it is once fet in motion by the impulfe, I (hall fuppofe, of ano- 

 ther body. Now, to maintain that body moves itfelf when it ei- 

 ther begins or continues motion, is, I think, downright materialifm ; 

 as it takes from mind that eflential quality of moving body, by 

 which all the operations of nature are carried on. And here we 

 may obferve, that Sir Ifaac has carried the dodtrine of materialifm 

 farther than any other author, antient or modern : For he has laid 

 it down as an axiom ; and what is more, he has given to body not 

 onlv the power of moving itfelf, but intelligence alfo ; by which 



it 



