388 A X T I K N T M E T A P H Y S I C S. Book V. 



the Motion is perfcdly fimple, without any centrifugal or centripe- 

 tal inclination. 



Thus far, I argue, from the mod certain of all knowledge, Confci- 

 oufnefs ; and I proceed further, by the following argument from ana- 

 logy, which, I think, cannot deceive me — As I am fure that my Body 

 is not moved by an external caufe, but by an internal principle of 

 movement ; fo every other Body, whether Animal or Vegetable, or- 

 ganized or unorganized, is moved in the fame manner, either in a 

 ftraight line, or a curve, when it is impoffible that any external 

 caufe of their Motion can be afligned. And this analogy I carry to 

 the Heavens : For, believing Mind and Body to be the fame there 

 that they are here, I fay that the Bodies there are moved in the fame 

 manner, when no external caufe of their Motion can be afligned ; 

 and, therefore, that the Planets perform their Elliptical Motions by 

 the operation of Mind, but in a manner more perfedl than Animals 

 here on Earth can perform them, as not being divided into joints or 

 limbs, and therefore moving altogether or not at all. 



And I think I have given a fatisfadory reafon, why Mind fhould 

 move Body in a curve, without any divifion of the Motion ; where- 

 as, it is impoflTible that Body can do fo. And the reafon is, that 

 Mind moves by inceffant energies, fo that it can vary the direcStion 

 in every inftant of the Motion : And therefore I think I have pro- 

 ved my theory, not only from fadt and obfervation, but a priori^ 

 from the nature of Mind, the moving power. 



It is, clearly, therefore, not true, what the Jefuit commentators 

 upon the Principia have laid down as a general propofition, and, in- 

 deed, as an axiom. That all Motion is, by its nature, redilineal ; for, 

 if this were true, there could be no fuch thing in Nature as a Circle 

 or Ellipfis, whether defcribed by Bodily Impulfe, or by Mind, every 



fuch 



