INTRODUCTION 



THE problems which mankind is compelled to face 

 are at once old and new, - - much older than man 

 himself in so far as they are the problems of life, and 

 growth, and reproduction ; yet ever new, since man- 

 kind progresses, and creates for itself conditions 

 which have never existed before. There are two 

 reasons why we cannot safely go back to even the 

 wisest of the ancients, to get from them adequate 

 counsel for the direction of our modern life. One is, 

 that we are no longer situated as they were : after 

 two or three thousand years of development, our 

 modern society necessarily presents many complex 

 features of which they knew nothing, and could not 

 have foreseen. The other is, that we represent the 

 maturer age of our species, with accumulated knowl- 

 edge and records of experience behind us - - knowl- 

 edge and experience dearly won, and constituting a 

 precious guide to conduct. The mature man looks 

 back with pleasure and longing to the days of his boy- 

 hood, but he does not appeal to his boyish thoughts 

 for the guidance of his later life. Yet the ancient 

 and modern meet as the result of the most recent 

 researches. Paradoxically, the discovery of innumer- 

 able details, the revelation of undreamed-of complex- 

 ities, leads us back to a better conception of the 

 essential simplicity of nature. Natural law, the un- 

 derlying unity in the midst of diversity, stands more 

 clearly revealed today than ever before, and we are 

 nearer than we ever were to a true philosophy. Thus 

 we appeal to the totality of existence, past and present, 

 and every fact has its place in our system, and teaches 

 some lesson. The mind, however, is limited in its 

 powers, and for practical purposes it is necessary to 



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