Preface to the First Edition. 



Consequently we have first to explain what we, and 

 what our antagonists mean by instinct and intelligence. 

 This will lead to a correct use of the terms. Secondly, 

 we must examine the true relation of instinct to intel- 

 ligence in animal life. This investigation will show, 

 whether intelligence in its genuine meaning may be 

 attributed to animals, or whether man is the only intel- 

 ligent being in the created world. For the same pur- 

 pose we shall soon publish a further essay on the com- 

 parative mental faculties of ants, of higher animals and 

 of man, which will be in close connection with and rest 

 upon the present work. 



