11 



to perceive that the operation of the same 

 causes might perpetuate the regular mo- 

 tions of the planetary system? Why do 

 we note facts with accuracy, or collect 

 them with diligence? why do we inter- 

 rogate nature by experiment? Is it not 

 because we wish to prove some of our 

 own opinions to be true, or the opposing 

 opinions of others to be false ? or, because we 

 wish to enlarge the boundaries of science 

 in a direction in which we think they 

 admit of extension? What induces one 

 person to prohibit another from theo- 

 rizing? Is it not because he has himself 

 attempted it in vain, and therefore deems 

 the attempt unavailing ? 



Feelings and opinions are the chief 

 sources of all our intellectual conduct : we 

 ought therefore to cultivate good and ho- 

 norable feelings, and to scrutinize opinions, 

 with a view to entertain none but those 



