2o8 Heredity. 



plexity of the other to allow of the one being the cause and the 

 other the effect. 



This would be the place to consider the famous theory of the 

 relations between genius and idiocy and insanity (Moreau of 

 Tours, Lelut). In it we should find many arguments for our thesis 

 on the disproportion between effects and causes in the physical 

 world. But not to dwell on this point, we confess that most of the 

 criticisms which have been made on this doctrine do not appear 

 very conclusive. If the authors had maintained the identity of 

 insanity and genius, as regards the facts which manifest them as, 

 for example, that the lucubrations of a madman are of equal value 

 with the works of Newton, or of Goethe the assertion would be 

 so monstrous that we could only regard it as a joke. But what 

 have they maintained? That the secondary causes, the organic 

 conditions of genius and insanity, seem to be almost identical ; so 

 that it is only by reason of accessory circumstances that a certain 

 nervous organization produces grand, artistic, or scientific creations 

 instead of expending itself on the dreams of a madman. 



Plainly, in order to reach a conclusion on this point we need a 

 large number of well-attested, well-interpreted, and well-verified 

 facts. But the only arguments that have been brought against this 

 thesis are sentimental ones, which possibly are only prejudices ; 

 and it is probable that if we knew clearly and scientifically the 

 conditions on which genius is produced, we should find much 

 to surprise us. 



In our opinion, what has excited most hostility against this 

 doctrine is that unconscious materialism which leads us to attach 

 so much importance to the organic conditions of phenomena. 

 But, even though from the point of view of physiological experi- 

 ence there existed between the causes of insanity and those of 

 genius only insignificant differences, would there be any less 

 difference between the two from the standpoint of psychological 

 and social experience ? The analogy between the causes would in 

 no degree change the enormous difference between the effects. 

 Even were genius the result of a certain state of the cerebral mass, 

 it would, nevertheless, still be the most exalted thing in the world. 

 The diamond has not lost its value since it has been discovered 

 that it is carbon. As John Stuart Mill well says, ' It is only for 



