INTRODUCTORY. 55 



that all human thought as well as all mental and natural 

 development reveal the existence of two factors, — that 

 there exist, as it were, two poles which form independent 

 centres of life and development. 



In the same degree as the desire has become more 

 pronounced to unify Thought and Knowledge, the 

 apparent dualism, so evident to common - sense, has 

 become more and more accentuated. In fact, as I stated 

 in the beginning of this Introduction, the desire to dis- 

 cover the underlying unity has primarily revealed the 

 existing contrast and the necessity of first clearly defining 

 and understanding it. 



Accordingly we find running through nearly all the 

 philosophical theories and speculations of the different 

 schools, the attempt to grasp more completely and define 

 more clearly that inherent dualism, frequently, indeed, 

 with the tacit or pronounced intention of dissolving it 

 in some unifying conception. Nearly every phase of 46. 

 philosophical thought has thus coined its special terms phUosopMe 



systems. 



wherewith to define this two-sidedness or polarity which 

 exists everywhere in and around us. Kant spoke of 

 " phenomena " and " noumena," of " pure theoretical " and 

 " pure practical reason " ; Schopenhauer writes of " the 

 world as Will and Intelligence " ; Schelling strove all 

 through tlie many phases of his philosophical career to 

 complete the " negative " by a " positive " philosop"hy ; 

 Herbert Spencer places " the Unknowable " in opposition 

 to " the Knowable," and even Comte's philosophy finds 

 room for " the Incognoscible." 



Of all these different terms in which the same idea 

 finds various expression, that which gives to the active 



