66^. THE POPULAR SCIENCE MONTHLY, 



However all this may be, it is to individual things that we must 

 refer the first beginnings of knowledge, the interest and the facility of 

 acquisition. There are great inequalities in this interest and conse- 

 quent facility ; many individual objects inspire no interest at all in the 

 first instance ; while some of these become interesting afterward, in 

 consequence of our discovering in them relationships to things of in- 

 terest. 



One notable distinction among the objects of knowledge is the dis- 

 tinction between movement or change, and stillness or inaction. It 

 is movement that excites us most ; still-life is rendered interesting by 

 reference to movement. We are aroused and engrossed by all moving 

 things ; our attention is turned away from objects at rest to contem- 

 plate movements ; and we imbibe with great rapidity the impressions 

 of moving objects. 



This brief survey of the sphere of individuality and of the various 

 attractions presented by individuals is preparatory to the consideration 

 of the most arduous part of knowledge the knowledge of generals or 

 generality. All the difficulties of the higher knowledge have reference 

 to the generalizing process the seeing of one in many. The arts of 

 the teacher and the expositor are supremely requisite in sweetening 

 the toil of this operation. At the present stage, however, the question 

 is to assign the motives connected with general knowledge as distinct 

 from individual knowledge. 



General knowledge, represented by science, consists in holding to- 

 gether, by a single grasp, whole classes of objects, of facts, of opera- 

 tions. This must, by the very nature of the case, be more severe than 

 holding an individual. To form an idea of one tree that we have 

 repeatedly surveyed at leisure, round and round, is about the easiest 

 exertion whether of attention or of memory. To form an idea of ten 

 trees partly agreeing and partly differing among themselves is mani- 

 festly an entirely altered task ; it is to exchange comparative simplicity 

 for arduous complexity ; yet this is what is needed everywhere in the 

 higher knowledge. 



The first emotional effect attendant on the process of generalizing 

 facts, and serving to lighten the intellectual burden, is the flash of 

 identity in diversity, an exhilarating charm that has been felt in every 

 age by the searchers after truth. Many of the grandest discoveries in 

 science have consisted, not in bringing to light any new individual fact, 

 but in seeing a likeness between things formerly regarded as wholly 

 unlike. Such was the great discovery of gravitation. The first flash 

 of the recognition of a common power in the motions of the planets 

 and the flight of a projectile on the earth was unutterably splendid ; 

 and, after a hundred repetitions, the emotional charm is unexhausted. 



With the emotion of exhilarating surprise at the discovery of like- 

 ness among things seemingly unlike, there is another grateful feeling, 

 the relief from an intellectual burden. This appears at first sight a 



