212 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 3 8 



the silliest nonsense imaginable, but cannot agree as to which it is, 

 it is clear that there is more than a difference of opinion; there must 

 be some defect of understanding also. Intelligent men do not thus 

 differ about that which they comprehend equally. It, therefore, 

 becomes a matter of importance to state this principle precisely, so 

 that we shall at least know what we are doing when we bless or curse 

 it. And in seeking to assess its value, we must avoid the error of 

 ascribing greater or less weight to the opinion of a physicist than to 

 that of another. Einstein is perfectly right in saying that if this 

 principle holds for him as a physicist, it holds for him also if he is not 

 a physicist; and M. Maritain offers him a license which he cannot 

 accept when he allows him to apply the principle in physics but not 

 outside. If we talk nonsense, and plead in extenuation that we are 

 only talking as physicists, we fall short of the ideal of rational speech, 

 distinguished precedent notwithstanding. The question must be 

 considered on general rational grounds: are we to admit the unob- 

 servable into our scheme of things or are we not? We must give an 

 answer which is independent of the particular scheme which we want 

 to uphold. 



Let me for a moment adopt the legal method, and state the case for 

 each side independently, as an advocate might state it. Take first 

 the case for the principle. It is necessary, say its supporters, as a 

 safeguard against irresponsible invention. If we allow that an entity 

 might exist and be significant to thought, although it is essentially un- 

 observable, what is there to prevent us from postulating any number 

 of such entities and invoking them to remove any difficulty that might 

 arise? Suppose, for instance, I assert that there is a binkum sitting 

 on the table in front of me, and that this tremendous fact, rightly 

 understood, is the final, completely satisfying solution of the problem 

 of evil. If you reject the principle in question, you have no grounds 

 for denying the statement. You may say that you cannot detect my 

 binkum, but I reply that of course you cannot, because he is unobserv- 

 able. If you want to know how his existence solves the problem of 

 evil, I say that it is its nature to do so, and the definition of him, ac- 

 cording to your own contention, is quite independent of any means 

 you adopt to investigate him. If you ask, "What is a binkum, any- 

 way?", I reply that that is immediately evident; I cannot put it into 

 words, but everyone knows what a binkum is. If you retort that you 

 do not know, I shrug my shoulders and say that you must be speaking 

 as a physicist. 



Stupid as this example sounds, it contains a precise parallel to the 

 case of simultaneity. M. Maritain and those who agree with him 

 claim that the simultaneity of spatially separated events is something 

 independent of our means of observing it. When asked what it is, 

 they claim that its nature is immediately evident and that everyone 



