CHAPTER XVII 



SUMMARY OF THE STAGES OF CORRELATION 



i. THE broad fact dealt with in the preceding chapters 

 is the adaptation of human and animal action to the 

 requirements of life and growth. Such adaptation we have 

 found to involve a certain correlation, to put it in the 

 most general terms possible, between the experiences and 

 actions of the individual and of the race. In the character 

 of the correlation found at different stages there is an 

 immense difference, and as is the nature of the correlation, 

 such is the adequacy, subtleness, and comprehensiveness of 

 the adaptation, and such also the ''requirements of 

 existence " which the organism seeks to meet. At one 

 end of the scale we have a method of correlation based on 

 the principle of heredity, and working out in the course of 

 many generations and through the extinction of a majority 

 of individuals, a structure fitted to respond with some- 

 thing approaching the regularity of a machine, to those 

 promptings of the environment or of the inward mechanism 

 which concern the safety of the individual and the per- 

 petuation of the species. Adaptation at this stage, though 

 often a model of precision in its working, is seen never- 

 theless in its narrowest and most primitive shape. For 

 each act is merely a response to a stimulus or set of stimuli 

 which under normal circumstances gives the required result, 

 but, where the environment deviates from the normal, 

 there is little or no power of making the necessary 

 readjustments. Lastly, the requirements of existence 

 which action is adapted to secure are the requirements of a 



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