1 1 8 PRODUCTION OF IDEAS. SECT. XIV. 2. 



figures ; and hence they cannot change place with 

 each other without difturbing or changing the 

 figure of the whole. 



Our idea of TIME is from the fame fource, but 

 is more abftracted, as it includes only the com- 

 parative velocities of thefe variations of figure ; 

 hence if it be afked, How long was this book in 

 printing ? it may be anfwered, Whiift the fun was 

 pa'iling through Aries. 



Our idea of PLACE includes only the figure of 

 a group of bodies, not the figures of the bodies 

 themfelves. If it be aiked, where is Nottingham- 

 fhn'e, the anfwer is, it is furrounded by Derby- 

 mire, Lincolnlhire, and Leiceflerfhire ; hence place 

 is our idea of the figure of one body furrounded 

 by the figures of other bodies. 



The idea of SPACE is a more abftracted idea of 

 place excluding the group of bodies. 



The idea of NUMBER includes only the particu- 

 lar arrangements, or diftributions of a group of 

 bodies, and is therefore only a more abftracted 

 idea of the parts of the figure of the group of 

 bodies s thus when I fay England is divided into 

 forty counties, I only fpeak of certain divifions of 

 its figure. 



Hence arifes the certainty of the mathematical 

 fciences, as they explain theie properties of bodies, 

 which are exactly refembied by our ideas of them, 

 whilft we are obliged to collect almoft all our other 

 knowledge from experiment ; that is, by obferv- 

 ing the effects exerted by one body upon another. 



3. Of the Penetrability of Matter. 



The impoflibility of two bodies exifling together 

 in the fame fpace cannot be deduced from our idea 

 of folidity, or of figure. As foon as we perceive 

 the motions of objects that furround us, and learn 



that 



