A NEGLECTED PROBLEM 485 



797. The extent to which thinking power may be influence! by 

 the formal training received during early manhood cannot easily 

 be observed in the individual. When trying to analyse the degree of 

 intelligence displayed by him, we do not know what part to attribute 

 to innate capacity, what to formal training, and what to various 

 other influences, such as those exercised by his companions, all of 

 which contribute to his intellectual development and status. If 

 we meet a clever man and approve the system by which he was 

 trained, we are apt to attribute his efficiency mainly to training ; 

 if we disapprove of the system, we tend to assign it to innate 

 capacity. Owing to lack of systematic inquiry, this question of 

 what is ' innate ' and what is ' acquired ' in the human mind, though 

 the most important of all practically, is yet the most neglected 

 problem of psychology. The consequent uncertainty, combined 

 with the difficulty of ascertaining the precise results of this or that 

 system of mental training and then comparing them with the results 

 obtained by other systems, has led to a vast diversity of opinion as 

 to which system is the best, some authorities advocating one, some 

 another, and some holding, apparently, that so much is innate that 

 all systems produce nearly the same results in the end. 1 It is 

 possible, however, to overcome the difficulty in some measure. 



798. We found that the solution of the problem of the causation 



the medical curriculum or the affairs of everyday life that, when the examination 

 on them was over, they were promptly forgotten by all except the few students 

 who adopted zoology as a profession or as a hobby. The professor's convictions 

 were countered by the convictions of other professors of physiology, patho- 

 logy, medicine, surgery, and the like. His experiments were met by accounts 

 of other experiments (extraordinarily misinterpreted), by details about cats, 

 almost as legendary as Bo-Peep's sheep, that had left their tails behind them in 

 traps and doorways and had borne tailless offspring ever afterwards, by stories 

 about human mothers who had seen moving sights and borne marked children, 

 and about consumptives, alcoholics, syphilitics, and imbeciles whose children 

 were similarly affected. Their reasoning was founded on credulity and confusion 

 of thought, but 'the students had been so trained that they were unable to per- 

 ceive its weakness. But, if the zoologist, instead of stating his convictions or 

 appealing to evidence which his pupils could not verify, had carefully explained 

 the distinction between variations and modifications, pointed out the difficulty 

 of believing that the latter could affect the germ-plasm in such precise ways as to 

 be reproduced in the child as ' innate ' characters, and had then appealed to the 

 facts of ordinary experience and of human evolution against disease, he would 

 have supplied his audience with data and thoughts pregnant and unforgettable 

 because they would have linked up with subsequent experiences, and with a 

 mental training which would have enabled them to appraise at their true worth 

 the puerilities of professors who argued, for example, that " acquirements must 

 be transmissible, for every character must have had a beginning, and therefore 

 must have been acquired by some one who handed it on to his descendants." 

 1 See 708. 



