THE REAL WORLD 381 



The terminal argument against any realist position is this : does not 

 quantum mechanics produce conceptual enormities that explode 

 forever the absurd human pretension to find the world intelligible? 

 The most-cited evidence is, no doubt, the disturbing dualism of wave 

 and particle. Deferring to the opinion of the vast majority of con- 

 temporary physicists, let us suppose that, to render a full account 

 of the electron, we must make use of both wave and particle analo- 

 gies our everyday experience teaches us to regard as fundamentally 

 incompatible. Even as a fact this would not entail the conclusion 

 that the concept "electron" is riven by some deep antinomic flaw. 

 Observe that the incompatability is at most between two analogies 

 we introduce to help us think about a microcosmic entity unlike any- 

 thing encountered in everyday experience. Actually the apparently 

 contradictory analogies do help physicists to so integral a concept of 

 the electron that many can, with Born, think of it as an entity essen- 

 tially real "in the usual meaning of the word." 



How much of the mystification connected with quantum me- 

 chanics arises from our insistence on using words where, as Bohr 

 observes, words simply wont suffice! 



... all our ordinary verbal expressions bear the stamp of our cus- 

 tomary forms of perception, from the point of view of which the ex- 

 istence of the quantum of action is an irrationality. 



The necessarily verbal nontechnical exposition of quantum mechan- 

 ics may then well make it appear utterly unintelligible. But it is not 

 necessarily unintelligible. Indeed, most of the apparent unintelli- 

 gibilities never even arise in the necessarily mathematical technical 

 exposition that is the proper vehicle of the theory. Those with some 

 bitter youthful experience of mathematics may distrust the implica- 

 tion that there are things and situations that words make obscure 

 and mathematics clear. Yet, far from the dread realm of quantum 

 mechanics, Cohen indicates that, with our own hands, we can easily 

 produce just such things and situations. 



. . . how many people can imagine a piece of paper that does not 

 have two distinct sides; or a vessel where there can be no line of de- 

 marcation between inside and outside? Moreover, when we actually 

 produce the former of these ( a Mobius strip or Kummer surface ) and 

 ask what will happen if it is repeatedly cut through the middle, the 



