4o8 POPULAR SCIENCE MONTHLY 



the same movements to reach them; apart from that, one can not just 

 see what they could have in common. 



But, given an object, we can conceive many different series of move- 

 ments which equally enable us to reach it. If then we represent to 

 ourselves a point by representing to ourselves the series of muscular 

 sensations which accompany the movements which enable us to reach 

 this point, there will be many ways entirely different of representing 

 to oneself the same point. If one is not satisfied with this solution, 

 but wishes, for instance, to bring in the visual sensations along with 

 the muscular sensations, there will be one or two more ways of repre- 

 senting to oneself this same point and the difficulty will only be in- 

 creased. In any case the following question comes up: Why do we 

 think that all these representations so different from one another still 

 represent the same point? 



Another remark: I have just said that it is to our own body that 

 we naturally refer exterior objects; that we carry about everywhere 

 with us a system of axes to which we refer all the points of space, and 

 that this system of axes seems to be invariably bound to our body. It 

 should be noticed that rigorously we could not speak of axes invariably 

 bound to the body unless the different parts of this body were them- 

 selves invariably bound to one another. As this is not the case, we 

 ought, before referring exterior objects to these fictitious axes, to sup- 

 pose our body brought back to the initial attitude. 



{To be continued.) 



