Heredity of the Intellect. 67 



parlance, Are common sense, insanity, genius, talent, subtlety, 

 aptitude for abstract studies, hereditary ? 



In order to reply, we will examine the question from the 

 two-fold standpoint of theory and fact, of metaphysics and 

 experience. Reason will show that the heredity of intellect is 

 possible, experience that it is real. 



If we admit the heredity of the lower modes of intellect and 

 facts are here decisive logic alone ought to convince us that it 

 extends to all intellect, for it is admitted by all schools of thought 

 that this faculty is essentially one. Psychology has always dis- 

 tinguished different modes of the faculty of knowing, and, indeed, 

 the analytical study of intellect is only possible on that condition. 

 But these are but differences in the way of looking at them, not 

 specific differences. In the same way, phrenologists have thought 

 that they could assign to each faculty a special portion of the brain ; 

 but, even had their view been sustained, such localization would in 

 no degree have invalidated the unity of the intellect itself. How- 

 ever far back the question may be carried, every inquiry into the 

 ultimate nature of intellect must necessarily issue in one or other 

 of these two conclusions : either it is an effect, of which the cause is 

 the organism ; or it is a cause, of which the effect is all that exists 

 or can be known. The first hypothesis is called materialism, the 

 second idealism. We shall see, taking our stand on reasoning 

 only, that between these two hypotheses and the heredity of the 

 higher modes of intellect there exists no contradiction, no logical 

 incompatibility. 



There is no difficulty in the materialistic hypothesis; for if it be 

 admitted that thought is only a property of living matter, then, as 

 heredity is one of the laws of life, it must therefore be also one of 

 the laws of thought. Or, in more precise terms, intellect is a 

 function whose organ is the brain ; the brain is transmissible, as 

 is every other organ, the stomach, the lungs, and the heart; the 

 function is transmissible with the organ; therefore intellect is 

 transmissible with the brain. Physiological heredity involves, as 

 a necessary consequence, psychological heredity in all its forms. 



On the other hand, the idealistic hypothesis seems to stand in 

 utter opposition to heredity of intellect ; but, as will be seen, this 

 opposition is not so radical as would at first appear. 



