240 SCIENCE AND PHILOSOPHY OF THE ORGANISM 



primitive form was to signify a " thing." So it conies that 

 advocates of the space-substance theory generally introduce 

 still another kind of inorganic " substance," which they call 

 merely distinctly marked elements of their space. But these 

 also have the character of uuchangeableness except in 

 respect to motion, and are almost identical with the atoms 

 of the other theory. 



In fact, there seems to be some force compelling the 

 human mind to admit some substance in space and not 

 merely space as the substance. The principle of the 

 constancy of the sum of all inorganic or material substance 

 would then be guaranteed for the simple reason that its 

 coming out of space or its coming into space is quite an 

 unimaginable and unthinkable event. Here, indeed, are 

 the very sources of the aprioristic principle of the conserva- 

 tion of material substance. 



There exists a very close relationship between the 

 principle of the conservation of substance and the principle 

 of the conservation of energy : both of them in some respect 

 resting upon the character of (formal) space as an all- 

 embracing something which neither may be left nor be 

 entered. It is probably this relationship that has seduced 

 some modern authors into asserting the identity of substance 

 and energy, a doctrine which seems to us to be absolutely 

 impossible. For this assertion forgets that what is 

 measured by " ergs " is only the amount of causality as 

 far as the latter has quantity and is therefore measurable, 

 whilst substance relates to what is not touched by causality 

 at all. The two principles of conservation relate to two 

 absolutely different branches of ontology. Energy " is ' 

 not, but is realised in change ; substance is. 



