Opinions on Isolation. 141 



when compared with those which once divided the 

 opinions of not a few still living men ? And if we are 

 bound to feel this, are we not bound further to feel 

 that the very intensity of our disputations over these 

 residual matters of comparative detail, is really the 

 best earnest that can be given of the determination 

 of our quest determination which, like that of our 

 fathers, cannot fail to be speedily rewarded by the 

 discovery of truth ? 



Nevertheless, so long as this noise of conflict is 

 in the Senate, we cannot wonder if the people are 

 perplexed. Therefore, in conclusion, I may ask it to 

 be remembered exactly what are the questions and 

 the only questions which still divide the parties. 



Having unanimously agreed that organic evolution 

 is a fact and that natural selection is a cause, or 

 a factor in the process, the primary question in debate 

 is whether natural selection is the only cause, or 

 whether it has been assisted by the co-operation of 

 other causes. The school of Weismann maintain that 

 it is the only cause ; and therefore deem it worse 

 than useless to search for further causes. With this 

 doctrine Wallace in effect agrees, excepting as regards 

 the particular case of the human mind. The school 

 of Darwin, on the other hand to which I myself 

 claim to belong believe that natural selection has 

 been to a considerable extent supplemented by other 

 factors ; and, therefore, although we further believe 

 that it has been the "main" factor, we agree with 

 Darwin himself in strongly reprobating all attempts 

 to bar a priori the progress of scientific investigation 

 touching what, if any, these other factors may be. 

 Lastly, there are several more or less struggling 



