INDUCTION: 115 



provisional hypothesis. In the case of Pan- 

 genesis this was not true. Darwin gave the 

 following as the principal reasons for believing 

 in natural selection : " (i) It is a true or recog- 

 nized cause; (2) from the analogy of change 

 under domestication by man's selection, and 

 (3) chiefly from this view connecting under an 

 intelligible point of view a host of facts." To 

 this may be added a fourth, which he men- 

 tioned to Huxley in connection with the third, 

 as being the reasons why younger scientists 

 would choose his theories rather than the doc- 

 trine of creation; namely, that it would enable 

 them to search out new lines of investigation. 



Let Pangenesis be tried by these four tests. 

 In the first place, it was not even claimed that 

 there was any proof, either direct or indirect, 

 of the existence of the gemmules. As a cause 

 which had been actually observed, they had no 

 existence. Secondly, while analogy is often a 

 strong collateral argument, and was so in the 

 case of natural selection, it was a treacherous 

 support in the case of Pangenesis. Perhaps as 

 many analogies were violated, as was pointed 

 out by Delpino and others, by the conception 

 of the gemmules as it could muster to its sup- 

 port; and one of the first essentials of an 

 argument from analogy is that the points of 



