CHAP. XII] AND PERCEPTION. 173 



" It is a known part of our constitution that wlien our 

 sensations cease, by the absence of their objects, some- 

 thing remains. After I have seen the sun, and by shut- 

 ting my eyes see him no longer, I can still think of him. 

 I have still a feeling, the consequence of the sensation 

 which though I can distinguish it from the sensation and 

 treat of it as not the sensation, but something different 

 from the sensation is yet more like the sensation than 

 anything else can be ; so like that I call it a copy, an 



image, of the sensation Another name by 



which we denote this trace, this copy of the sensation, 



which remains after the sensation ceases, is IDEA 



The word IDEA in this sense will express no theory what- 

 soever ; nothing but the bare fact, which is indisputable. 

 We have two classes of feelings : one, that which exists 

 when the object of sense is present ; another, that which 

 exists after the object of sense has ceased to exist. The 

 one class of feelings I call SENSATIONS, the other class of 



feelings I call IDEAS As each of our senses has 



its separate class of sensations, so each has its separate 

 class of ideas. We have ideas of sight, ideas of touch, 

 ideas of hearing, ideas of taste, and ideas of smell." 

 These copies of sensations may recur singly or in 

 clusters, so that they, like Sensations, are and have been 

 long classified as ' simple 'and * complex.' For the pro- 

 cess of recurrence itself, which of course varies much in 

 complexity, James Mill proposed the term IDEATION. 



But in referring to the sensations derived from, and 

 the realization of the nature of, an ' external object,' wo 

 have passed beyond the range of ' Sensation proper,' and 

 have encroached upon what is commonly considered as 

 ' Perception proper.' The full meaning and explanation of 

 this statement will become plain if we briefly consider the 



