128 THE WOELD-ENEEGY 



that can come within the possible range of our knowing 

 are those determined hy the relations of bodies to each 

 other. 



Such relations are fixed or absolute in the sense that 

 they are inseparable from the bodies. If the bodies exist 

 the relations also exist necessarily or " absolutely." Thus 

 in every case of the relation of body to body in space com- 

 ing under our observation we have an example of abso- 

 lute knowledge, though it is also a knowledge of rela- 

 tions. 



But again, when the relations between the parts of 

 a physically constituted system are considered, such 

 relations will be found to undergo change. It is here, 

 indeed, that we find the appropriate realm of measure 

 and of relativity in estimate of values. A change of 

 distance, or of velocity, or of direction, is equal, or greater, 

 or less, in comparison with some other change of dis- 

 tance, or of velocity, or of direction. And these changes 

 are represented in empirical space ; that is, in a space 

 rendered significant by the presence of objects. 



But also, with such changes of relation, there is 

 introduced the element of possible confusion. A given 

 body, A, considered with reference to a given other body, 

 B y will appear to be moving in one direction ; while, in 

 comparison with a third body, C, it will appear to be 

 moving in a contrary direction. Thus motion appears 

 to contain its own dialectic, through which it exhibits 

 its own absolute relativity. For example, suppose any 

 three bodies, a, b and c, to be moving in the same 

 direction along the same straight line, c being first 

 and a last. If c has the greatest velocity and b 

 the least, then b will appear to be moving away from c 



