276 Heredity. 



nature of the rock, and the slope of the precipice 

 events and circumstances all of which depend on natural 

 laws; but there is no relation between these laws and 

 the purpose for which each fragment is used by the 

 builder. In the same manner the variations of each 

 creature are determined by fixed and immutable laws; 

 but these bear no relation to the living structure which 

 is slowly built up by the power of selection, whether this 

 be natural or artificial selection." 



"If our architect succeeded in rearing a noble edifice, 

 using the rough wedge-shaped fragments for the arches, 

 the longer stones for the lintels, and so forth, we should 

 admire his skill even in a higher degree than if he had 

 used stones shaped for the purpose. So it is with selection, 

 whether applied by man or by nature; for though varia- 

 bility is indisputably necessary, yet when we look at some 

 highly complex and excellently adapted organism, varia- 

 bility sinks to a quite subordinate position in comparison 

 with selection, in the same manner as the shape of each 

 fragment used by our supposed architect is unimportant 

 in comparison with his skill" ( Variation, xxi. p. 301). 



It is quite possible that Darwin may be right in at- 

 tributing the modification and adaptation of organisms 

 almost entirely to the influence of natural selection, 

 and, at the same time, wrong in his belief that the vari- 

 ations are fortuitous. Several critics have pointed out 

 that if it is true that variations have no relation what- 

 ever to the needs of the organism, there are grave diffi- 

 culties in the way of natural selection; but the theory 

 rests upon too firm a basis to be easily set aside, and 

 these objections have hardly received the attention 

 which they fairly deserve, for those authors who have 

 painted them out have, at the same time, attacked the 

 general theory in a hostile spirit without proposing any- 



