Xll AUTHOR'S PREFACE. 



last hundred years under the name of " philosophy " 

 is far from assimilating our hard-earned treasures of 

 experimental research. On the other hand, we have 

 to admit, with equal regret, that most of the repre- 

 sentatives of what is called " exact science " are 

 content with the special care of their own narrow 

 branches of observation and experiment, and deem 

 superfluous the deeper study of the universal con- 

 nection of the phenomena they observe — that is, 

 philosophy. While these pure empiricists " do not 

 see the wood for the trees," the metaphysicians, on 

 the other hand, are satisfied with the mere picture of 

 the wood, and trouble not about its individual trees. 

 The idea of a " philosophy of nature," to which both 

 those methods of research, the empirical and the 

 speculative, naturally converge, is even yet contemp- 

 tuously rejected by large numbers of representatives 

 of both tendencies. 



This unnatural and fatal opposition between Science 

 and Philosophy, between the results of experience and 

 of thought, is undoubtedly becoming more and more 

 irksome and painful to thoughtful people. That is 

 easily proved by the increasing spread of the immense 

 popular literature of " natural philosophy " which 

 has sprung up in the course of the last half-century. 

 It is seen, too, in the welcome fact that, in spite of 

 the mutual aversion of the scientific observer and the 

 speculative philosopher, nevertheless eminent thinkers 

 from both camps league themselves in a united effort 

 to attain the solution of that highest object of inquiry 



