Plasticity and Intelligence 21 



the social life is worked out in the Social and EtJiical 

 Interpretations. The further extensions which the theory 

 of biological recapitulation has recently undergone, prom- 

 inent among which is the theory that regression shows 

 itself first in individuals and afterward in the same direc- 

 tions in the species, should also find confirmation if they 

 be true, or the reverse if they be not true, from the facts 

 of genetic psychology. 1 



2. Natural and Functional Selection : Plasticity 



and Intelligence 



Apart from the question of recapitulation, which I have 

 given this prominence both from its general character 

 and also from the fact that it has survived very consider- 

 able criticism in recent literature, we find certain points 



had a natural history in the animal series, we are at liberty to use what we 

 know of the correspondence between nervous process and conscious process, 

 in man and the higher animals, to arrive at hypotheses for its solution; to 

 expect general analogies to hold between nervous development and mental 

 development, one of which is the deduction of race history epochs from 

 individual history epochs through the repetition of phylogenesis in ontogene- 

 sis, called in biology ' Recapitulation ' ; to view the plan of development of 

 the two series of facts taken together as a common one in race history, as we 

 are convinced it is in individual history by an overwhelming weight of evi- 

 dence; to accept the criteria established by biological research, on one side 

 of this correspondence, the organic, while we expect biology to accept 

 the criteria established, on the other side, by psychology; and, finally, to 

 admit with equal freedom the possibility of an absolute beginning of either 

 series at points, if such be found, at which the best-conceived criteria on 

 either side fail of application. For example, if biology has the right to make 

 it a legitimate problem whether the organic exhibits a kind of function over 

 and above that supplied by the chemical affinities which are the necessary 

 presuppositions of life, then the psychologist has the equal right, after the 

 same candid rehearsal of the facts in support of his criteria, to submit for 

 examination the claim, let us say, that ' judgments of worth ' represent a 

 kind of deliverance which vital functions as such do not give rise to." (First 

 ed., pp. 14 ff.) 



1 See also Chap. XIII. 5, on ' Concurrence and Recapitulation.' 



