LECTURE I. 41 



racters of mind have thought, and may 

 think differently ; for neither can confute 

 the other. One party, considering the more 

 gradual and rapid changes which take place 

 in surrounding bodies, and all the phaeno- 

 mena of motion and of rest, as effects of 

 some subtile, invisible substance or sub- 

 stances pervading all nature, whilst the 

 other may attribute them to inherent pro- 

 pensities in the atoms themselves. 



I have led you thus far, Gentlemen, to 

 shew you the rock on which the ancient 

 fortress of scepticism stands erected, and it 

 is evidently so unimpregnable that it has 

 been a secure retreat for ages, and may still 

 continue to be so. Whilst its tenants keep 

 within their own territories, or even de- 

 mean themselves peaceably abroad, I, for 

 one, would never attempt t6 molest them, 

 nor prevent them from the full enjoyment of 

 their native apathy and inactivity of mind. 

 But when they make excursions to annoy 

 their neighbours, and in disguise too, it 

 seems necessary to unmask them, and send 

 ihem home again. 



