ABSTRACTION. 



43' 



than that of not being clear : it is not 

 applicable to the case at all. Among 

 the phenomena, therefore, which we 

 are attempting to connect by means 

 of the conception, we must suppose 

 that there really is an agreement, 

 and that the conception is a concep- 

 tion of that agreement. In order, 

 then, that it may be clear, the only 

 requisite is, that we shall know ex- 

 actly in what the agreement con- 

 sists ; that it shall have been care- 

 fully observed and accurately remem- 

 bered. "We are said not to have a 

 clear conception of the resemblance 

 among a set of objects when we have 

 only a general feeling that they 

 resemble, without having analysed 

 their resemblance, or perceived in 

 what points it consists, and fixed in 

 our memory an exact recollection of 

 those points. This want of clearness, 

 or, as it may be otherwise called, 

 this vagueness, in the general con- 

 ception, may be owing either to our 

 having no accurate knowledge of the 

 objects themselves, or merely to our 

 not having carefully compared them. 

 Thus a person may have no clear 

 idea of a ship because he. has never 

 seen one, or because he remembers 

 but little, and that faintly, of what 

 he has seen. Or he may have a per- 

 fect knowledge and remembrance of 

 many ships of various kinds, frigates 

 among the rest, but he may have no 

 clear, but only a confused idea of a 

 frigate, because he has never been 

 told, and has not compared them 

 sufficiently to have remarked and re- 

 jnembered in what particular points 

 a frigate differs from some other kind 

 of ship. 



It is not, however, necessary, in 

 order to have clear ideas, that we 

 should know all the common proper- 

 ties of the things which we class to- 

 gether. That would be to have our 

 conception of the class complete as 

 well as clear. It is sufficient if we 

 never class things together without 

 knowing exactly why we do so, — with- 

 out having ascertained exactly what 

 agreements we ar« about to include 



in our conception ; and if, after hav- 

 ing th\is fixed our conception, we 

 never vary from it, never include in 

 the class anything which has not 

 those common properties, nor exclude 

 from it anything which has. A clear 

 conception means a determinate con- 

 ception ; one which does not fluctuate, 

 which is not one thing to day and 

 another to-morrow, but remains fixed 

 and invariable, except when, from the 

 progress of our knowledge or the cor- 

 rection of some error, we consciously 

 add to it or alter it. A person of clear 

 ideas is a person who always knows 

 in virtue of what properties his clas.ses 

 are constituted, what attributes are 

 connoted by his general names. 



The principal requisites, therefore, 

 of clear conceptions aro habits of 

 attentive observation and extensive 

 experience, and a memory which re- 

 ceives and retains an exact image of 

 what is observed. And in proportion 

 as any one has the habit of observing 

 minutely and comparing carefully a 

 particular class of phenomena, and an 

 accurate memory for the results of the 

 observation and comparison, so will 

 his conceptions of that class of phe- 

 nomena be clear ; provided he has 

 the indispensable habit, (naturally, 

 however, resulting from those other 

 endowments,) of never using general 

 names without a precise connota- 

 tion. 



As the clearness of our conceptions 

 chiefly depends on the carefulness and 

 accuracy of our observing and com- 

 paring faculties, so their appropriate- 

 ness, or rather the chance we have of 

 hitting upon the appropriate concep- 

 tion in any case, mainly depends on 

 the activity of the same faculties. He 

 who by habit, grounded on sufficient 

 natural aptitude, has acquired a readi- 

 ness in accurately observing and com- 

 paring phenomena, will perceive so 

 many more agreements and will per- 

 ceive them so much more rapidly than 

 other people, that the chances are 

 much greater of his perceiving, in any 

 instance, the agreement on which the 

 important consequenoes depend 



