2oo Heredity. 



debated under the singular titles of ' the problem of individua- 

 tion,' of ' hoccity,' and of 'hseccity.' This barbarous jargon has 

 been ridiculed, but yet, if we turn from words to things, we can- 

 not deny that this problem pressed upon the schoolmen, and 

 was of paramount importance. Modern philosophy, as it seems 

 to us, has been far more concerned with what is general laws, 

 genera, species than with what is individual. Now, if we are 

 hence led to consider what is general as the true reality, the 

 logical conclusion is that the individual is only a momentary 

 phenomenon, of no importance, the ephemeral result of laws 

 which intersect and combine in a thousand ways during the end- 

 less evolution of the universe. To use the words of Dr. Lucas, we 

 should have to affirm resemblance by rejecting diversity : heredity 

 would be the law, spontaneity the exception. If, on the other 

 hand, we regard the individual as a reality, as a sort of nomad, 

 governed and hemmed in on all sides by the laws of nature, 

 but whose essential, impenetrable being is never modified, then 

 we set diversity above resemblance, and sacrifice heredity to 

 spontaneity. 



We have here undertaken only a study of experimental psych- 

 ology, and hence we need not discuss this difficult metaphysical 

 problem. We may note, in passing, that if we descend to the 

 ground of experience, it is impossible to deny absolutely the exist- 

 ence of diversity, for it is demonstrated by facts. There are in 

 nature no two beings alike. When we see a large flock of sheep 

 we may regard most of them as copies of one another, but the 

 practised eye of the shepherd can distinguish each one. The 

 courtiers of Alfonso X. sought in vain for two leaves like each 

 other. But though diversity exists, we do not believe that it is 

 only explicable by a special law. 



If we consider the act of generation under the simplest possible 

 conditions, as a single being engendering another, without the 

 intervention of any disturbing cause, it is absolutely impossible to 

 conceive how the product could differ from the producer ; for 

 there is no reason for admitting one deviation rather than another, 

 such deviation would be an effect without a cause. Linnaeus' 

 aphorism, like produces like, strikes us therefore with all the 

 evidence of an axiom. But in reality the process does not take 



