S-i HABIT a:^d intelligence. [chap. 



scientific tliouglit, perfectly differentiated from feeling, 

 needs the action of will to make it work. 

 Analogy of The analogy here traced is between the mental functions 

 organic ^^^ q^q bodily Organs. I do not lay claim to any ori- 

 ^oT^k ginality in pointing it out. But there is a further analogy, 

 between organic growth and mental gTOwth, and between 

 the formation of organic tissue and of w'hat by a bold 

 metaphor may be called mental tissue ; which, so far as 

 I am aware, has not yet been traced by any one in all its 

 closeness. 

 The It is a well-known truth, that every organism is built 



organism ^^^^ ^f ^j^g substance of its food. This is perfectly 



structed familiar with respect to animals, and is equally certain of 

 foodty the plants, though their food is less visible, consisting chiefly 

 organic in- ^f ^j-^g carbon contained in the carbonic acid of the air. 

 igence . ^^^ ^^^^ .^ evidently not a full account of the process of 

 nutrition. Tliere must be not only materials, but some- 

 thing that builds with the materials ; and this something 

 is the principle of life, or the organizing power, which, as 

 I have stated my reasons for believing, is intelligent, 

 though unconscious.^ 

 so mind The growth of mind is analogous with this. As all 



is con- materials come to the organism from without, so the 

 out of ini- materials of knowledge come to the mind from without, 

 '^r^ nse bv ^^ ^^^ shape of impressions on the senses. All knowledge 

 the mental begins with sensatiou ; we have no " innate ideas : " pre- 

 genceV vious to sensatiou we have neither ideas, nor knowdedge, 

 nor any actual mental existence whatever, but only the 

 possibility, or to speak more accurately the potentiality, of 

 a mental existence. This is admitted by all. To quote 

 the old scholastic axiom, " There is nothing in the mind 

 but what it has derived from sensation." But this is 

 evidently not a full account of the process of mental 

 growth. There must be not only materials, but something 

 that builds with the materials. As Leibnitz expressed it, 

 we must modify the scholastic axiom, and say : " There is 

 nothing in the mind but what it has derived from sensa- 

 tio]i, except the mind itself." From the point of view to 



1 See the chapters on Natural Selection and on Intelligence. 



