87 *^® "^°*h <^"d the candle 



that one should have adapted itself to the other. I am not 

 saying I don't beheve it did. On the whole I think I do, at 

 least with one reservation. But sometimes I can't help say- 

 ing to myself, "A man who will believe that will believe 

 anything." 



Since Darwin's day the fact that evolution did, somehow 

 or other, take place has been made overwhelmingly clear. 

 Because that fact could not really be doubted, most stu- 

 dents felt compelled to accept what seemed to be the best 

 available explanation of "how" it could possibly have hap- 

 pened. Yet the fact remains that a great many students 

 have been just a little unhappy about that 'Tiow" and that 

 a good deal of the work which has been done since Dar- 

 win's day has been concerned with an attempt to make 

 the whole thing seem a little more credible. 



Nearly everybody came to feel that Darwin's summary 

 reliance on minute, accidental variation and natural selec- 

 tion was a bit too casual. The discovery that organisms 

 were capable of sudden big-step "mutations" as well as 

 minute variations helped. All sorts of experiments were 

 designed to prove that some slight accidental advantage 

 like the lighter color of a mouse living on sand really did 

 increase significantly its chances of survival. The mathe- 

 matically minded got into the game, notably Sir Ronald 

 Aylmer Fisher who recently summarized in formidable 

 equations his contention that chance is not chance when 

 statistically studied and that the "progress" made in the 

 course of evolution was no more merely fortuitous than 

 the profits of the proprietor of a roulette wheel are. Given 

 time enough he is bound to win. The "laws of probabiUty" 

 take the chanciness out of chance. 



