ELEMENTARY PARTICLE — SCHRODINGER 187 



In both explanations the wording seems to suggest that the uncer- 

 tainty or lack of precision refers to the attainable knowledge about a 

 particle rather than to its nature. Indeed, by saying that we disturb 

 or change a measurable physical quantity we logically imply that it 

 has certain values before and after our interference, whether we know 

 them or not. And in the first explanation, involving the wave, if we 

 call it a guiding wave how should it guide the particle on its path, if the 

 I)article has not got a path ? If we say the wave indicates the probabil- 

 ity of finding the particle at A, or at B, or at C — this seems to imply 

 that the particle is at one, and one only, of these places ; and similarly 

 for the velocity. (Actually the wave does indicate both probabilities 

 simultaneously, one by its extension, the other by its wave numbers.) 

 However, the current view does not accept either ubiety or velocity as 

 permanent objective realities. It stresses the word "finding." Finding 

 tlie particle at point A does not imply that it has been there before. 

 We are more or less given to understand that our measuring device 

 has brought it there or "concentrated" it at that point, while at the 

 same time we have disturbed its velocity. And tliis does not imply 

 that the velocity "had" a value. We have only disturbed or changed 

 the probability of finding this or that value of the velocity if we 

 measure it. The implications as to "being" or "having" are miscon- 

 ceptions, to be blamed on language. Positivist philosophy is invoked 

 to tell us that we must not distinguish between the knowledge we 

 can obtain of a physical object and its actual state. The two are one. 



6. CRITICISM OF THE UNCERTAINTY RELATION 



I will not discuss here that tenet of positivist philosophy. I fully 

 agree that the uncertainty relation has nothing to do with incomplete 

 knowledge. It does not reduce the amount of information attainable 

 about a particle as compared with views held previously. The conclu- 

 sion is that these views were wrong and we must give them up. We 

 must not believe that the completer description they demanded about 

 what is really going on in the physical world is conceivable, but in 

 practice unobtainable. This would mean clinging to the old view. 

 Still, it does not necessarily follow that we must give up speaking and 

 thinking in terms of what is really going on in the physical world. It 

 has become a convenient habit to picture it as a reality. In everyday 

 life we all follow this habit, even those philosophers who opposed it 

 theoretically, such as Bishop Berkeley, Such theoretical controversy 

 is on a different plane. Physics has nothing to do with it. Physics 

 takes its start from everyday experience, which it continues by more 

 subtle means. It remains akin to it, does not transcend it generically, 

 it cannot enter into another realm. Discoveries in physics cannot in 



