EDITOR'S PREFACE. XV 



The translator wishes it to be said that all the altera- 

 tions made for this edition have been either requested or 

 approved by the author, only some few footnotes of a 

 bibliographical sort having been added after Professor 

 Groos saw the proofs. The additions made by the trans- 

 lator in the notes are put in brackets, both those which 

 Professor Groos has seen and also the very few others 

 which were subsequently added. The reader will also 

 notice from the title-page that the author has now been 

 called from his former position at Giessen to the chair in 

 Philosophy in the University of Basel. 



J. M. B. 



