CH. XV.] THE COMPOSITION OF MIND. 116 



part of the faucet, and the protuberance where the horizontal 

 piece is fitted upon it, awaken tactual sensations which co- 

 exist with the sensation of temperature, and the automatic 

 comparison of these sensations which constitutes the per- 

 ception of the faucet goes on unhindered. To concentrate 

 consciousness upon the feeling of temperature requires a 

 voluntary act of attention, induced by the desire to know 

 how warm the water is getting. As the water becomes very 

 much warmer, so as to be slightly uncomfortable, the per- 

 ception of the faucet does not become gradually less vivid, 

 but it tends to disappear entirely, and consciousness tends 

 to occupy itself exclusively with the feeling of temperature. 

 Only through a distinct voluntary effort can the perception 

 be made to come into the foreground of consciousness. If, 

 now, there comes a sudden spurt of very hot water, the 

 tactual perception of the faucet is for the moment entirely 

 excluded, and the perceptive act implied in the estimation 

 of the degree of temperature is also expelled from conscious- 

 ness, which is occupied entirely with the sensation of pain, 

 inducing a violent withdrawal of the hand. Here sensation, 

 reaching a maximum, has quite driven out the group of 

 tactual perceptions, and even visual perceptions are to that 

 extent held in abeyance, that for the moment they cease to 

 occupy the attention. If, now, a piece of soap is taken from 

 its dish, the newly-aroused group of sensations — of weight, 

 hardness, smoothness, and the rest — exist in minimum in- 

 tensity, and consciousness is occujoied, not with them, but 

 with the presence of the piece of soap : perception tends to 

 exclude sensation. 



"What, now," inquires Mr. Spencer, "is the real nature of 

 this mutual exclusion ? Is it not an instance of the general 

 kact that consciousness cannot be in two equally distinct 

 btates at the same time ; and that in proportion as the pre- 

 dominance of one state becomes more marked, the suppres- 

 Bion of other states becomes more decided ? I cannot know 



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