INTRODUCTION. 81 



or shadow of material existence. Though demanding for 

 its growth an outer stimulus, and unable to proceed very 

 far without external correctives, I nevertheless maintain 

 that the human mind in its individual and collective life 

 encloses an independent source of reality which contact 

 with outer things and thought in all its various forms 

 has to reveal, to preserve, and to develop. To what 

 extent this has been done in our century is the question 

 I propose to answer. "With this object in view I shall 

 try to gather my observations and my narrative around 

 the prominent and novel constructive ideas which have 

 sprung up in the course of the century, not omitting 

 the great development which the purely formal side of 

 thought, the method of research, has undergone. Such 

 constructive ideas are those of energy, its conservation 

 and dissipation ; the doctrine of averages, statistics, and 

 probabilities ; Darwin's and Spencer's ideas of evolution ze. 

 in science and philosophy ; the doctrines of individualism spencer's, 



and Lotze's 



and personality, and Lotze's peculiar view of the world ^ a s s tructive 

 of "values" or "worths." Around these centres of thought 

 cluster the many critical oppositions, the great contro- 

 versies of radical or conservative opponents. As regards 

 these, I shall welcome all radicalism which lays bare the 37. 

 roots of our ideas, which delves deep into the ground sort o'fradi- 



. calism. 



of our opinions and principles, or which points out new 

 methods by which we may test the correctness and con- 

 sistency of our axioms. As such I consider the spirit 

 infused by Kant into all modern thought. That other 

 radicalism, which merely roots up, which destroys with- 

 out building, which fails to find any ground of certainty, 

 simply because human thought and observation may after 

 VOL. i. F 



