PREFACE TO THE THIRD EDITION. XXXI 



mock at pliilosopliic tendencies and researches ; and the 

 latter knows no more severe charge to bring against me 

 than that I seek to miite empiricism and philosophy, 

 experience and idea, " observation and reflection." I am 

 certainly firmly convinced that a really scientific study of 

 nature can no more dispense with philosophic reflection, 

 than can healthy philosophy ignore the results of natural 

 scientific experience. "An exact empiricism," without 

 those philosophic thoughts which combine and explain the 

 raw material of facts, merely results in the accumulation 

 of a lifeless store of knowledge ; on the other hand, 

 " speculative philosophy " which knows nothing of the firm 

 basis afforded by natural scientific observation, can only 

 produce transient cloud-pictures. The most intimate com- 

 bination and blending of emx^iricism and philosophy can 

 alone enable us to construct a permanent and sure scientific 

 structure. I still hold as decidedly as ever the much- 

 abused views which I expressed, ten years ago, about this 

 matter in my Generelle MorpJiologie, and the fundamental 

 ideas which I have here reproduced. 



Moreover, he must be very one-sided or short-sighted 

 who does not recognize the natural approximation, which 

 is now becoming more close in all branches of liuman 

 knowledge, between experimental and reflective study. The 

 enormous enlargement of the field of empiric knowledge 

 which has been brought about by the progress of the last 

 half-century, has resulted in a corresponding specialization 

 of separate researches, and consequently in an isolation of 

 diverging aims which cannot possibly continue to satisfy. 

 All thoughtful observers feel, more acutely in consequence 

 of this, that they must raise themselves from the wearisome 



