SENSORY AND RATIONAL DISCRIMINATION 127 



vision. We see much that we do not observe, and 

 we observe what an animal does not see. Thus it 

 is matter of frequent remark that we did not notice 

 objects which we had seen, and which we would have 

 noted if our eyes had been directed upon them by 

 ourselves for observational ends. On the other hand, 

 when we observe that all the stones in a bank, being 

 opened for a roadway, have been rounded by the 

 action of water, we remark what no animal sees. 

 Thus the structure and function of special sense are 

 separate from rational power, exercised in observa 

 tion. We here identify a power not included among 

 the functions of the sensory system. 



In all observation, there is interpretation of the 

 various effects of sensory impression. We invariably 

 compare these with the facts, of a past experience. 

 No explanation of this is found in recurrence or 

 remembrance of sensations. Without memory, we 

 could not make and record observations ; but observa 

 tion is distinct, and puts memory to use, brings it 

 into exercise, in order that an observation may be 

 completed. We make observations only by using 

 associations of similarity and dissimilarity in judging 

 of objects. We deal with experiences, like and unlike, 

 past and present, always recognising outward differ 

 ences by reference to inward. Without this, there 

 could be nothing but continuous feeling, or feeling 

 merely rising and falling. By comparison of im 

 pressions, we gain our knowledge of things. 



In prosecuting observation there is a further 

 advance. We are always representing to ourselves 

 the class to which an object belongs. The object 

 observed is not merely a thing. It is not merely 



