6 ESSAYS anp OBSERVATIONS 
we conceive the motion of the body as an 
effect produced by a proper caufe. In this 
cafe the body does not act, but is acted up- 
on. This, tho’ an evident diftinétion, does 
not exclude felf-motion from being alfo con- 
fidered as an effect ina certain light, viz. 
an effect produced by a being upon itfelf. 
Every thing which moves, and is not 
barely moved or acted upon, mutt be endu- 
ed with a power of motion. For this power 
is involved in the very conception of {felf- 
motion. And the term power may be equal- 
ly applied to animate and inanimate beings, 
fuppofing them to be equally felf-movers. 
WHETHER matter in any cafe be endued 
with a power of motion, is a. celebratéd 
queftion, which is generally refolved in the 
negative: and, as this queftion cannot be o- 
verlooked in the prefent fpeculation, I fhall 
endeavour to examine it with all the accu- 
racy pofiible. 
Matter is generally reprefented as alto- 
- gether unactive and inert; and indeed ina 
fuperficial view the fact appears to be fo. 
The bulk of the things about us feem to 
be at reft, and we lay our account that they 
will continue in that ftate, unlefs acted upon 
by 
