6 ESSAYS AND OBSERVATIONS 



thing to others : But both are equally inca- 

 pable of a definition. They are fimple ob- 

 je(5ls of fight, and perhaps of touc h. De- 

 prive us of thefe two fenfes, and we could 

 never have the lead notion either of reil or 

 motion. 



Wh E N a being moves itfelf or moves, we 

 conceive the being as adling ; and, in this 

 view, motion is a fpecies of adlion. But, 

 when a body is moved by being a(fled up- 

 on, we conceive the motion of the body as 

 an efFedl produced by a proper caufe. In 

 this cafe the body does not adl, but is 

 adted upon. This, though an evident di- 

 llindion, does not exclude felf-motion 

 from being alfo confidercd as an efiecfl in 

 a certain light, viz. an effed produced by 

 a being upon itfelf. 



Every thing which moves, and is not 

 barely moved or aded upon, muft be en- 

 dued with a power of motion. For this 

 power is involved in the very conception 

 of felf-motion. And the term poiver is 

 equally applicable to animate and inani- 

 mate beings, fuppofing them to be equally 

 felf-movers. 



Whether 



