o SENSORIAL ACTIONS. Srcr; XI. * 



be procured immediately ; and, fecondly, the muf- 

 cular action necefiary for this purpofe. 



You voluntarily call up all your ideas of caufa- 

 tion, that are related to the effect you defire, and 

 voluntarily examine and compare them, and at 

 length determine whether to afcend the tree, or to 

 gather ftones from the neighbouring brook, is eaiier 

 to praclife, or more promiling of fuccefs ; and, 

 finally, you gather the ftones, and repeatedly fling 

 them to diflodge the fruit. 



Hence then we gain a criterion to diftinguifh 

 voluntary acts or thoughts from thofe caufed by 

 fenfation As the former are always employed 

 about the means to acquire pleafurable objects, or 

 the means to avoid painful ones ; .while the latter 

 are employed in the pofleffiun of thofe, which are 

 already in our power. 



Hence the activity of this power of volition pro- 

 duces' the great difference between the human and 

 the brute creation. The ideas and the actions of 

 brutes are almoft perpetually employed about their 

 prefent pleafures, or their prefent pains ; and, except 

 In the few inftances which are mentioned in Sec- 

 tion XVI. oh inftinct, they feldom bufy themfelves 

 about the meansof procuring future blifs, orof avoid- 

 ing future mifery ; fo that the acquiring of lan- 

 guages, the making of tools, and labouring for 

 jmoney, which are all only the means to procure 

 pleafures ; and the praying to the Deity, as another 

 means to procure happinefs, are character! (tic of 

 human nature. 



4. As there are many difeafes 'produced by the 

 quantity of the fenfation of pain or pleafure being 

 too great or too little ^ fo are there difeafes produc- 

 ed by the fufceptibility of the conftitution to mo> 

 tions caufable by thefe fenfation s being too dull or 

 too vivid. This fufceptibility of the fyftem to fen- 

 iitive motions is termed fenfibility, to diftinguifh it 



from 



