SECT. IX. i. VOLUNTARY MOTIONS. 47 



brought into aftion ; as was {hewn in the preceding 

 fection, and were called fenfitive motions. The 

 general tendency of thefe motions is to arreft and 

 to poflefs the pleafure, or to diflodge or avoid the 

 pain : but if this cannot immediately be accom- 

 plifhed, defire or averfion are produced, and the 

 motions in confequence of this new faculty of the 

 fenforium are called voluntary. 



1. i. Thofe mufcles of the body that are attach- 

 ed to bones, have in general their principal conne- 

 tions with volition, as 1 move my pen or raife my 

 body. Thefe motions were originally excited by 

 irritation, as was explained in the fection on that 

 fubjecl, afterwards the fenfations of pleafure or pain, 

 that accompanied the motions thus excited, induc- 

 ed a repetition of them ; and at length many of 

 them were voluntarily practifed in fucceiiion or in 

 combination for the common purpofes of life, as in 

 learning to walk, or to fpeak ; and are performed 

 with ftrength and velocity in proportion to the 

 energy of the volition, that excites them, and the 

 quantity of fenforial power. 



2. Another great clafs of voluntary motions con- 

 fifts of the ideas of recollection. We will to repeat 

 a certain train of ideas, as of the alphabet back- 

 wards ; and if any ideas, that do not belong to this 

 intended train, intrude themfelves by other con- 

 nections, we will to reject them, and voluntarily 

 perfifl in the determined train. So at my approach 

 to a houfe which I have but once vilited, and that 

 at the diftance of many months, I will to recollect 

 the names of the numerous family I expect to fee 

 there, and I do recollect them. 



On this voluntary recollection of ideas our facul- 

 ty of reafon depends, as it enables us to acquire an 

 idea of the diffimilitude of any two ideas. Thus if 

 you voluntarily produce the idea of a right-angled 

 triangle, and then of a fquare ; and after having 



excited 



