SECT. XI. 2. 4. ACTIONS. 41 



ployed in the poncfiion of thofe, which are already in our 

 power. 



Hence the aftinty of this power of volition produces the 

 great difference between the human and the brute creation. 

 The ideas and the actions of brutes are alrnofl perpetually em- 

 ployed about their prefent pleafures, or their prefent pains ; and, 

 except in the few inftances which are mentioned in Section 

 XVI. on inftintf, they feldom bufy themfelves about the means 

 of procuring future blifs, or of avoiding future mifery ; fo that 

 the accquiring of languages, the making of to^ls, and labouring 

 for money, which are all only the means to procure pleafures ; 

 and the praying to the Deity, as another means to procure hap- 

 pinefs, are characleriflic 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 produced by the fufceptibility of the conftitu- 

 tion to motions cauiabie by thefe fenfations being too dull or too 

 vivid. This fufceptibility of the fyftem to fenfitive motions is 

 termed fe-nfibility, to diftinguifh it from fenfation, which is the 

 actual exiftence or exertion of pain or pleafure. 



Other clafTes of difeafes are owing to the exceflive prompti- 

 tude, or fluggimnefs of the conftitution to voluntary exertions, 

 as well as to the quantity of defire or of averfion. This fuf- 

 ceptibility of the fyftem to voluntary motions is termed volun- 

 tarity, to diftinguilh it from volition, which is the exertion of 

 defire or averfion ; thefe difeafes will be treated of at length in 

 the progrefs of the work. 



AJJo elation. 



III. i . It is not eafy to afllgn a caufe, why thofe animal move- 

 ments, that have once occurred in fucceflion, or in combination, 

 fhould afterwards have a tendency to fucceed or accompany 

 each other. It is a property of animation, and diftinguilhes this 

 order of being from the other productions of nature. 



When a child firft wrote the word man, it was diftinguifhed 

 in his mind into three letters, and thofe letters into many parts 

 of letters ; but by repeated ufe the word man becomes to his 

 hand in writing it, as to his organs of fpeech in pronouncing it, 

 but one movement without any deliberation, or fenfation, or ir- 

 ritation, interpofed between the parts of it. And as many fep- 

 arate motions of our mufcles thus become united, and form, as 

 it were, one motion ; fo each feparate motion before fuch union 

 may be conceived to confift of many parts or fpaces moved 

 through ; and perhaps even the individual fibres of our mufcles 



VOL. I. G have 



