PERCEPTION. 127 



the branch marked " Perception " is not intended to include 

 all that might possibly be included by the term if we did not 

 separately name the higher faculties to which I allude. 



Now concerning the development of Perception, I may 

 here make a general remark, which is first applicable at this 

 stage of mental evolution, and which continues to be appli- 

 cable to the development of all the faculties which we have 

 subsequently to consider. This remark is that we have ceased 

 to possess any data of a morphological kind — such as we had 

 in the case of Sensation and the pre-mental faculties of 

 adjustment — to guide us in our estimate of the degree of 

 elaboration to which the faculty has attained. That morpho- 

 logical evolution has here, as in the coarser instance of Sen- 

 sation, always gone hand in hand with psychical evolution, is 

 amply proved in a general way by the advancing complexity 

 of the central nerve-organs ; but just because this complexity 

 is so great, and the steps in morphological evolution which it 

 represents so refined, we are totally at a loss to follow the 

 process on its morphological side ; we are unable even dimly 

 to understand the mechanisms which we see. Therefore, in 

 order to estimate the ascending grades of excellence which 

 these mechanisms present, we require to look to what we may 

 most conveniently regard as the products of their operation ; 

 we have to use the mental equivalents as indices of the mor- 

 phological facts. 



"We have seen that Perception is essentially a process of 

 mentally interpreting Sensation in terms of past experience, 

 ancestral or individual. The successive steps in the elabora- 

 tion which this process undergoes in the course of its 

 evolution must now be considered. 



The first stage of Perception consists merely in perceiving 

 an external object as an external object, whether by the sense 

 of touch, taste, smell, hearing, or sight. But confining our- 

 selves, for the sake of brevity, to the sense of sight, in this 

 stage Perception Bimply amounts to a cognition of an object 

 in space, having certain space relations with other objects of 

 perception, and especially with the percipient organism. 



The next stage of Perception is reached when the simplest 

 qualities of an object are re-cognized as like or unlike the 



qualities presented by such an object in past experience. The 

 most universal of such qualities in objects pertain to size 

 form, colour, light, shade, rest, and motion; less universally 



