THE RELATIVITY OF SPACE. 103 



in such a way that when one of the centripetal wires 

 is traversed by a current, this current acts on a central 

 exchange, and so excites a current in one of the 

 centrifugal wires, and matters are so arranged that 

 several centripetal wires can act on the same centri- 

 fugal wire, if the same remedy is applicable to several 

 evils, and that one centripetal wire can disturb several 

 centrifugal wires, either simultaneously or one in 

 default of the other, every time that the same evil 

 can be cured by several remedies. 



It is this complex system of associations, it is this 

 distribution board, so to speak, that is our whole 

 geometry, or, if you will, all that is distinctive in our 

 geometry. What we call our intuition of a straight 

 line or of distance is the consciousness we have of 

 these associations and of their imperious character. 



Whence this imperious character itself comes, it 

 is easy to understand. The older an association is, 

 the more indestructible it will appear to us. But 

 these associations are not, for the most part, conquests 

 made by the individual, since we see traces of them 

 in the newly-born infant ; they are conquests made 

 by the race. The more necessary these conquests 

 were, the more quickly they must have been brought 

 about by natural selection. 



On this account those we have been speaking 

 of must have been among the earliest, since without 

 them the defence of the organism would have been 

 impossible. As soon as the cells were no longer 

 merely in juxtaposition, as soon as they were called 

 upon to give mutual assistance to each other, some 

 such mechanism as we have been describing must 

 necessarily have been organized in order that the 



