3 5 8 Problems of Organic Adaptation 



fundamentally dissimilar though superficially alike. And in 

 reply to Bergson it may be said that although the eye of 

 Pecten is in a single feature, namely, the inverted retina, 

 like the vertebrate eye, it is in other respects fundamentally 

 different. These eyes are not homologous and Bergson's 

 contention is groundless. 



Neither are the similarities between societies of ants and 

 men, and many other examples of a like nature which are 

 cited by Bergson, real homologies or examples of convergent 

 evolution. The similarities which are present are merely 

 such as are due to principles of universal application, such 

 as the extension of differentiation and integration from indi- 

 viduals or persons to colonies and states. Practically all 

 of Bergson's cases of convergent evolution are of this sort. 

 They indicate only the essential unity of all living things, 

 that certain properties are characteristic of all life and are 

 present in the simplest as well as in the most complex organ- 

 isms. They certainly do not prove that life processes are 

 indeterminate or that identical results may follow different 

 causes, and therefore that vital activity is non-mechanistic. 



It is true that it is often impossible to predict what living 

 things will do, but this is probably owing to the fact that 

 the factors involved are very numerous and complex. When- 

 ever the number of factors is large and the times and cir- 

 cumstances of their action numerous, it is difficult to predict 

 results, as is seen for example in so simple a phenomenon 

 as the weather. This is especially true of the behavior of 

 higher animals, for here the number of factors is much 

 greater than in many inorganic phenomena and the inter- 

 actions of these factors are most complex. Professor W. K. 

 Brooks used to comment upon the ease of predicting what 

 would happen when you kick a stone, as compared with the 

 difficulty of predicting the results of kicking a dog. In the 



