40 THE METHOD OF DARWIN. 



rare ability to reason out the consequences of 

 his hypotheses, and his unbending determina- 

 tion to test his reasoning by ruthless investiga- 

 tion made important inductions, deductions, 

 and analogies that were not true, and failed to 

 make deductions that should have thrust them- 

 selves upon him. He rarely, however, fell 

 into the old and vicious error of thinking that 

 reasoning of any kind is final proof. 



He built up a large inductive structure in 

 pangenesis only to see it rejected; he went 

 wrong in his deduction concerning the relation 

 between high degree of specialization and the 

 chances in favor of preservation of a species; 

 and was prevented by a bad analogy from 

 investigating the effects of cross- and self-fer- 

 tilization in plants until the subject was thrust 

 upon him by empirical observation. He was 

 as productive of hypotheses as Nature is of liv- 

 ing things, and, like her, he subjected them 

 all to the principle of natural selection. His 

 mind was so fertile in guesses and so quick in 

 testing them that he called much of his work 

 "fool's experiments. " But in this way nothing 

 escaped him. 



In recent years there has been made a for- 

 mal statement of the reasons why fertility in 

 hypotheses should be cultivated, and how they 



