<;e. XV.] THE COMPOSITION OF MIND. 113 



from the union of these inferences with those many others 

 through which the locality is recognized." ^ From this 

 example it appears that while, at the highest extreme, 

 perception emerges into reasoning, on the other hand at its 

 lowest extreme, as where a body is perceived to be rough or 

 hard, it borders very closely upon simple sensation. Pro- 

 ceeding, then, a step farther in our descending analysis, we 

 have to examine the character of the difference between per- 

 ception and sensation. 



Sensation, no less than perception, has a variety of grades. 

 At the one extreme it rises to a point where it is barely dis- 

 tinguishable from perception ; at the ether extreme it lapses 

 into an unconscious or sub-conscious psychical state. While 

 writing these lines the sum-total of my consciousness may 

 contain elements contributed by dull sounds of persons walk- 

 ing overhead, by the rumbling of wagons in the street, by 

 faint odours wafted from the kitchen, by soothing pulses of 

 sensation from the pipe held in my mouth, and by the occa- 

 sional striking of the cuckoo-clock, as well as by the pressure 

 exerted by the chair in which I am sitting, and the table 

 upon which my arm is resting, and the pen which is grasped 

 in my fingers. But, while I am absorbed in thought, none 

 of these elements rise into the foreground of consciousness : 

 though they are present as psychical states, as is shown by 

 the fact that the going out of the pipe or the failure of the 

 clock to strike is noticed, yet I become conscious of them, in 

 the ordinary sense of the word, " only when they pass a 

 certain degree of intensity," as when a child overhead falls 

 on the floor, or when the shriek and rumble of a passing rail- 

 way-train are added to the confused mass of out-door noises ; 

 " and only then can I be said to experience " these feelings 

 "as sensations." But when a psychical state rises into the 

 foreground of consciousness aui becomes known as a sensa- 

 tion, as when my finger happens to touch the heated pipe- 



* Spencer, Principles of Fsychology, voL ii. p. 245. 

 VOL, XL I 



