Nature of Evolutionary Progress 41 



pain or to the physical alteration in his finger in- 

 duced by the heat? How shall we find out whether my 

 change of vote is due to my change of opinion or only 

 to some physical change in my body? 



The case for the mechanist would be proved if it 

 could actually be shown that from a knowledge of the 

 movements and distribution of particles at some 

 period before life appeared, my behavior, the be- 

 havior of all animals and men, the course of history, 

 could be correctly computed and predicted without 

 taking into account sensations, emotions, opinions, 

 knowledge. But no one claims that this has been done, 

 or ever will be done, or indeed that, in fact, it can be 

 done. The idea merely is that it would be possible if 

 there were a sufficient knowledge of the distribution 

 and movement of the particles at some early period, 

 provided one were a sufficiently competent computer. 

 But this is a mere supposition, totally unfulfilled; a 

 mere speculation. It forms no foundation for the 

 acceptance of a positive doctrine or for the dogmatic 

 teaching of that doctrine. As Bergson has well said, 

 the doctrine of mechanism involves the sacrifice of 

 experience to the requirements of a system. The 

 motivation of the doctrine is indeed a practical one — 

 the desire to simplify the task of science. The uni- 

 verse would be so much easier to deal with if the laws 

 of its action were simple and uniform. Let us assume 

 therefore that they are simple and uniform ! The doc- 

 trine is a marked case of wishful thinking. 



The notion that actions are not influenced by sen- 

 sations and other mental experiences ; in other words, 



