278 Habit and Instinct. 



associated, the mental evolution is so completely sub- 

 servient to organic needs, that the biologist is somewhat 

 apt to forget that, no matter how close this association 

 may be, mental development has its own laws, and 

 requires distinctive if not independent treatment. On 

 this, however, it is needless now further to insist. We 

 may conclude this chapter by indicating concisely the rdl 

 of consciousness in organic evolution. 



In what was termed the merely organic phase oi 

 evolution, we may note, as the result of heredity, twc 

 products : first, congenital definiteness of structure or 

 responsive activity, subject, indeed, to variation, but other- 

 wise relatively fixed and stereotyped ; and, secondly, that 

 innate plasticity which renders possible modifications of 

 structure or mode of growth; so that, in virtue of this 

 second product, the individual possesses the power of 

 adapting itself to the special conditions of its own par- 

 ticular environment. Such modification is, in this phase 

 of evolution, purely organic, and altogether independent of 

 consciousness, which, if present, affords no guidance in the 

 process ; as, for example, in the adaptive modifications of 

 plants. 



The primary role of consciousness, as a factor in race- 

 progress, is to extend in a new way this individual 

 adaptability, so that by modifications of its modes of 

 responsive activity, as the outcome of conscious choice, 

 the organism may yet further accommodate itself to the 

 special conditions under which its life is passed. This it 

 does through the agency of a special organ of control 

 associated with the conscious symbolism of experience. 

 The guidance afforded by intelligence is an individual 

 matter, as is the experience on which it is based, and the 

 association which renders this experience possible ; and 

 the intelligent faculty in and through which behaviour can 



