196 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1950 



There is the following connection between our relation and the un- 

 certainty relation. The latter allows one at any moment to distinguish 

 a particle from its neighbors by locating it with an error considerably 

 smaller than the average distance I. But this entails an uncertainty in 

 p. On account of it, as the particle moves on, the uncertainty in the 

 location grows. If one demands that it still remain well below I after 

 the particle has covered the distance Z, one arrives precisely at the 

 above relation. 



But again I must warn of a misconception which the preceding 

 sentences might suggest, viz, that crowding only prevents us from 

 registering the identity of a particle, and that we mistake one particle 

 for the other. The point is that they are not individuals which could 

 be confused or mistaken one for another. Such statements are mean- 

 ingless. 



REFERENCES 



1. Mach, Ernst. 



1905. Erkenntnis und Irrtum. Leipzig. 



2. Russell, Bertkand. 



1948. Human knowledge, its scope and limits. London. 



3. DiELS, Hermann. 



1903. Die Fragmente der Vorsokratiker, Berlin. (The reference is 

 mainly to the fragment 125 of Democritus.) 



