PREFACE. Vii 



divides itself into two : the one, concerning the unconscious 

 intelligence that organizes the body ; the other, concerning 

 the conscious intelligence of mind. 



The inquiry concerning the nature of the organizing intel- 

 ligence involves an examination of that question of the origin 

 of species which, since the publication of Darwin's great work 

 on the subject, has probably attracted more interest than any 

 other scientific question. I agree with Darwin in the belief 

 that all species have been derived by descent with modification, 

 probably from one, certainly from a few, original germs : and 

 I further agree with him in attaching great importance to 

 " natural selection among spontaneous variations " as part of 

 the agency by which the modifications have been effected. But 

 I altogether differ from him, in that I believe the wondrous 

 facts of organic adaptation cannot have been produced by 

 natural selection, or by any unintelligent agency whatever. 



The latter part of the first volume is occupied with this 

 inquiry into the origin of species and the nature of the or- 

 ganizing intelligence. The first part of the second volume is 

 occupied with the parallel inquiry into the process of mental 

 growth and development, and the nature of mental intelligence. 

 As on the subject of organizing intelligence I have come to 

 a conclusion which is fundamentally opposed to that of Darwin, 

 so on this I have come to a conclusion which is fundamentally 

 opposed to that of the dominant psychological school in this 

 country : I mean that school which was founded, as I believe, 

 by Hartley, and to which Mill, Bain, and Herbert Spencer 

 belong. The characteristic point of their theory is, that they 

 endeavour to account for the whole mental nature by the single 

 principle of the association of ideas, or, as I call it, of mental 

 habit. I maintain, on the contrary, that in all mental intelli- 

 gence, as in organizing intelligence, there is an element not 

 derived from habit, and not resolvable into any unintelligent 

 force whatever. 



