THE METAPHYSICS OF SENSATION 261 



imaginary man perfect freedom to move, so as to 

 be able to glide in all directions over the bodies 

 with which it is in contact. Then with the con- 

 sciousness of that mobility, the notion of space of 

 three dimensions which is " Raum" or " room " 

 to move with perfect freedom is at once given. 

 But the notion that the tactile surface itself 

 moves, cannot be given by touch alone, which is 

 competent to testify only to the fact of change of 

 place, not to its cause. The idea of the motion 

 of the tactile surface could not, in fact, be attained, 

 unless the idea of change of place were accom- 

 panied by some state of consciousness, which does 

 not exist when the tactile surface is immoveable. 

 This state of consciousness is what is termed the 

 muscular sense, and its existence is very easily 

 demonstrable. 



Suppose the back of my hand to rest upon a 

 table, and a sovereign to rest upon the upturned 

 palm, I at once acquire a notion of extension, and 

 of the limit of that extension. The impression 

 made by the circular piece of gold is quite different 

 from that which would be made by a triangular, 

 or a square, piece of the same size, and thereby I 

 arrive at the notion of figure. Moreover, if the 

 sovereign slides over the palm, I acquire a distinct 

 conception of change of place or motion, and of 

 the direction of that motion. For as the sovereign 

 slides, it affects new nerve-endings, and gives rise 

 to new states of consciousness. Each of them is 



