388 THE KIDDLE OF THE UNIVEKSE. 



affirm to-day that the marvellous progress of modern 

 cosmology has solved this " problem of substance," or 

 at least that it has brought us nearer to the solution ? 



The answer to this final question naturally varies 

 considerably according to the standpoint of the philo- 

 sophic inquirer and his empirical acquaintance with 

 the real world. We grant at once that the innermost 

 character of nature is just as little understood by us 

 as it was by Anaximander and Empedocles 2,400 

 years ago, by Spinoza and Newton 200 years ago, 

 and by Kant and Goethe 100 years ago. We must 

 even grant that this essence of substance becomes 

 more mysterious and enigmatic the deeper we 

 penetrate into the knowledge of its attributes, matter 

 and energy, and the more thoroughly we study its 

 countless phenomenal forms and their evolution. We 

 do not know the " thing in itself " that lies behind 

 these knowable phenomena. But why trouble about 

 this enigmatic " thing in itself " when we have no 

 means of investigating it, when we do not even clearly 

 know whether it exists or not ? Let us, then, leave 

 the fruitless brooding over this ideal phantom to the 

 " pure metaphysician," and let us instead, as " real 

 physicists," rejoice in the immense progress which 

 has been actually made by our monistic philosophy of 

 nature. 



Towering above all the achievements and discoveries 

 of the century we have the great, comprehensive " law 

 of substance," the fundamental law of the constancy 

 of matter and force. The fact that substance is every- 

 where subject to eternal movement and transformation 

 gives it the character also of the universal law of 

 evolution. As this supreme law has been firmly 

 established, and all others are subordinate to it, we 



