TRADITION AND HEREDITY 457 



classes.^ Generally speaking, throughout the Middle Ages, so far 

 as is known, the so-called upper classes contributed more to 

 succeeding generations than the so-called lower classes. The 

 position is now reversed, and it would appear that in the later 

 days of Greece and Rome also the upper classes contributed less 

 to the population than the lower classes. It is possible that the 

 same may have been the case in other ancient empires. The 

 utmost importance has been attributed to the influence of this form 

 of differential fertility upon the course of history. Mr. McDougall, 

 for instance, writes as follows : ' Looking at the course of history 

 widely, we may see in the differentiation of the social classes by 

 the social ladder and in the tendency of the upper strata to fail 

 to reproduce themselves, an explanation of the cyclic course of 

 civilization.' '^ Clearly a careful inquiry into this subject is 

 needed. There are certain points to which attention may be at 

 once drawn, but we shall not be able to reach any definite con- 

 clusion until we have examined farther into the nature of the 

 modifications produced by differences in tradition between the 

 different classes. 



Here we may observe that it is altogether misleading to speak, 

 as Mr. McDougall does, of the lower classes as being ' drained ' 

 by the operation of the social ladder, even in England at the 

 present day where the chance of rising is as great, if not greater, 

 than it has ever been before. A very limited number can and 

 do rise. The ladder is not only steep and difficult to climb ; it 

 is also narrow and does not permit of many upon it at the same 

 time. Further, so great is the prestige of class that very few of the 

 descendants of those who have climbed ever sink back, and yet 

 among them the regression to the mean is always in operation. 

 In other words, supposing that the ancestors of those composing 

 the upper social classes to have been distinguished by desirable 

 mental qualities, their descendants, to whose disappearance so 

 much is attributed, are not distinguished by a similar superiority 

 to the average. 



Granting for the moment all that has ever been claimed 

 regarding the superiority of those who climb, the above con- 

 siderations modify the importance to be attributed to differential 

 fertihty. It may further be noticed that, although Mr. McDougall 



> Where, as in America, different racial stocks exist, differential fertility assumes 

 greater importance. See p. 320. '' McDougall, Group Mnul, p. 2G0. 



