312 CAUSATION 



For the atom we have no such insight into what is 

 behind the pointer readings. We believe that behind 

 all pointer readings there is a background continuous 

 with the background of the brain; but there is no more 

 ground for calling the background of the spontaneous 

 behaviour of the atom "volition" than for calling the 

 background of its causal behaviour "reason". It should 

 be understood that we are not attempting to reintroduce 

 in the background the strict causality banished from 

 the pointer readings. In the one case in which we have 

 any insight — the background of the brain — we have 

 no intention of giving up the freedom of the mind and 

 will. Similarly we do not suggest that the marks of 

 predestination of the atom, not found in the pointer 

 readings, exist undetectable in the unknown back- 

 ground. To the question whether I would admit that 

 the cause of the decision of the atom has something in 

 common with the cause of the decision of the brain, 

 I would simply answer that there is no cause. In the 

 case of the brain I have a deeper insight into the 

 decision; this insight exhibits it as volition, i.e. some- 

 thing outside causality. 



A mental decision to turn right or turn left starts one 

 of two alternative sets of impulses along the nerves to 

 the feet. At some brain centre the course of behaviour 

 of certain atoms or elements of the physical world is 

 directly determined for them by the mental decision — 

 or, one may say, the scientific description of that be- 

 haviour is the metrical aspect of the decision. It would 

 be a possible though difficult hypothesis to assume that 

 very few atoms (or possibly only one atom) have this 

 direct contact with the conscious decision, and that 

 these few atoms serve as a switch to deflect the material 

 world from one course to the other. But it is physically 



