10 MORRIS LOEB 



reached a class of about sixty-five substances, which we have 

 not yet been able to decompose or transform, and which we 

 call the elements. True, many chemists believe that these 

 elements are themselves composite, but whether this is so, 

 and whether indeed the supposed substances of a more primi- 

 tive order would be recognizable by chemical means, is a 

 question which we are unable to answer. At present we shall 

 assume that the chemist recognizes the existence of different 

 substances arising from different relations between the hypo- 

 thetical matter par excellence and the coordinate essence 

 which we call energy. 



In all this attempt to formulate the essential conditions of 

 material existence, the tendency of our mind is toward a sim- 

 plification of our standards of reference, toward a lessen- 

 ing of the number of pigeon-holes into which new ideas must 

 be put. We love to believe that the higher we ascend on the 

 scale of causation, the smaller becomes the number of co- 

 ordinate causes. Our experience appears to justify us in this 

 reasoning, and so, as I have said, we have arranged for our- 

 selves at that point where our experience appears to stop, 

 the fiction of these four principles, space, time, matter, and 

 energy. Let us not flatter ourselves, however, that this is an 

 achievement of modern physics. The speculations of philos- 

 ophers long ago led them to the same physical conceptions, 

 and if Aristotle's elements appear grosser to us, it is because 

 we have stripped off, as unessential, some of the accessory 

 qualities with which he had clothed the mathematical skele- 

 ton. Struggle as we may, we cannot rid our own few prin- 

 ciples of some quality in common and consequently ulterior: 

 above all things we give them alike that vague, awesome at- 

 tribute of existence: essences, let us call them, because they 

 appear to us to be the ultimate things that exist, according 

 to our mundane imagination. All that we tell ourselves is, 



