CONFORMITY WITH PLAN 329 



carried on for a number of years, he had shown that the plan 

 according to which a Paramecium develops remains constant 

 through many thousands of generations, and its place cannot 

 be taken by blind experimenting in Nature. 



Although the doctrine of " trial and error " completely 

 missed fire in the case of the genesis of the organism, Jennings 

 and his pupils cannot bring themselves to explain, by re- 

 cognition of a specific biological factor in Nature, the obvious 

 differences between organic and inorganic actions. On the 

 contrary, they try to get some understanding of the actions 

 of animals on the basis of human psychology. Like all 

 psychologists, in so doing they change their standpoint and 

 think themselves into that of the dog carrying the stick. 

 To be consistent, they should also think themselves into 

 the insect as it flies against the window, and put human ideas 

 into it. 



The outside observer is quite unsatisfied by this. He 

 wants to know an objective reason for the behaviour of the dog 

 and the fly, and he rejects presumptions that he cannot con- 

 trol. Accordingly he seeks for stimuli in the outside world 

 that might serve the dog and the fly as indications. And the 

 knowledge of these solves the problem completely as regards 

 function-actions. In so doing, he is conscious that the indica- 

 tions are drawn from his own appearance-world, and he does 

 not seek for the indication-signs that slumber perhaps in the 

 minds of the dog and the fly. 



TROPISMS 



J. Loeb, the founder of the doctrine of tropisms, comes 

 from a far too exact school of physics ever to try to explain 

 the observed life-processes by the aid of psychological hypo- 

 theses. He never seeks an explanation through the mind 

 of what takes place in space and time in full concreteness. 



y 



