THE RELATIVITY OF KNOWLEDGE 



tre. By the latter he classified the unknown 

 force which keeps the moon from tumbling 

 down upon the earth along with the familiar 

 force which urges a stone whirled at a sling's- 

 end to fly away upon a tangent. In each case 

 he did nothing but classify phenomena which 

 had hitherto remained unclassified; and this was 

 rightly felt to be a triumphant explanation — 

 although the ultimate nature of the forces oper- 

 ating remained as mysterious as before. 



If now we proceed still further, and ask in 

 what sense the force which makes apples fall 

 can be regarded as known by us, — we can 

 only reply, it is not known in itself, but only 

 in its manifestations throughout a number of 

 phenomena which can be classed together, and 

 any one of which is said to be known when it is 

 perceived to be like its congeners previously 

 presented to our consciousness. We know a 

 thing only when we classify it in thought with 

 some other thing ; only when we see it to be 

 like some other thing. In short, cognition is pos- 

 sible only through recognition. In the infant, 

 we may see that there are no cognitions until 

 the feelings awakened by the presence of ex- 

 ternal objects have been arranged into groups, 

 so that when certain sensations occur they may 

 be recognized as belonging to such or such 

 a group. And in the adult, as our examples 

 already cited suffice to show us, an object is 



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