Plasticity and Intelligence 23 



that organic variation is in a direction which furthers 

 accommodation, or ' educability,' by mental selection in 

 individuals (a correlation in development). In the latter 

 respect, the utility of plasticity, as permitting mental de- 

 velopment and selective accommodation, is so great that 

 it outweighs in evolution all other biological characters, 

 and as embodied in the brain, becomes the great outstand- 

 ing fact throughout the ascending series of mammalian 

 forms. Once given the presence of consciousness, with 

 its methods of psychological accommodation, and it carries 

 with it organic adjustment ; while the operation of variation 

 with selective survival tends to perfect it. 



Moreover, in psychophysical accommodation we have the 

 problem of selection set in a new form inside of the func- 

 tions of the organism itself. Consciousness, mind in any 

 form, is a character ; its functions are always psycho- 

 physical in their operation. How then can consciousness 

 select without violating parallelism ? In answer to this 

 it may be pointed out that accommodation is another 

 comparative conception ; for it is only by an application 

 of the operation of natural selection in the form of 

 survival from overproduced functions, such as move- 

 ments, dispositions, etc., that consciousness can effect 

 selective adjustments ; that is, there is no other way short 

 of a miracle. This in general outline is the conception 

 of functional selection. 1 So a completed view of psycho- 

 physical accommodation requires (first) natural selection, 

 operating upon (second) variations in the direction of 

 plasticity, which allows (third) selective adjustment through 



1 Worked out in Mental Development on the basis of the theory of ' sur- 

 plus discharges ' of Spencer and Bain. See also the recent work on Animal 

 Behaviour, pp. 163 f., by Professor Lloyd Morgan. 



