THE PRINCIPLES OF SCIENCE 181 



the life which fits it. The dry land created the feet which walk it. Our 

 situation has created the mind which deals with it. It is an earthly 

 situation. Along with the sea it has created in us the wonder of the 

 sea. The situation engenders the reaction to it. If the agent is terres- 

 trial and the reaction is terrestrial is not the medium of the reaction 

 terrestrial? The medium is the mind. 



Simplicity sigillum veri. Newton still assumed some absolute sim- 

 plicity of the world when he wrote : 



. . . Nature does nothing in vain, and more is in vain when less will 

 serve; for Nature is pleased with simplicity, and affects not the pomp 

 of superfluous causes. 



But even when we posit no more than congruity of world and mind, 

 we must continue to impute special status to what we judge "simple." 

 If our scrutiny of nature seems to show any "superfluous causes," we 

 then come quite naturally to suppose our examination defective or 

 incomplete. Thus in biology each diflFerentiated tissue or organic man- 

 ifestation is confidently assumed to have, if not a purpose, then a 

 function we set ourselves to discover. Von Frisch's entire epoch- 

 making study of bees took departure, he tells us, from his flat rejection 

 of the claim that the colors of flowers have no biological significance. 

 Teleology, today not longer acceptable as an argument, conserves its 

 power as heuristic guide. Von Bruecke, indeed, draws the general 

 conclusion that, although teleology is a lady with whom the contem- 

 porary biologist is reluctant to be seen in public, he finds it impossible 

 to live without her. 



A number of more "respectable" implications attach to our convic- 

 tion that we must find nature simple when we see her truly. Consider 

 for example JefiFreys' comment: 



The actual behavior of physicists in always choosing the simplest 

 law that fits the observations therefore corresponds exactly to what 

 would be expected ... if they considered the simplest law as hav- 

 ing the greatest prior probability. 



Finding difficulty with JefiFreys' whole concept of prior probability, I 

 regard the characteristic behavior he so accurately reports as just one 

 more direct consequence of our acceptance of the principle of intelli- 

 gibility. The simple law is just that species of law we know how to 

 explain by theoretical derivation. Supposing that all genuine laws are 



