236 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1933 



has hardly progressed at all. The world therefore lives forever. 

 Near its apparent boundary, the world in Keats' words is : 



For ever piping songs for ever new . . . 

 For ever panting and for ever young. 



If we call " creation " the indescribable and iinobservable state out 

 of which the systems were bom (for us, 2,000,000,000 years ago) 

 then we may say that there are always events in the world for which 

 antecedent creation is only just a thing of the past. We cannot 

 observe the event of creation itself, even in the limit, for it is only 

 an occurrence in our present for nebulae moving with the speed of 

 light, and these if they existed would be invisible, unobservable. 



The event of creation itself is discreetly mantled in invisibility. 

 Not only can we not go behind creation, we cannot go right up to it; 

 but we can get within an arbitrarily short experience of it, by obser- 

 vations that are in principle capable of being carried out. There is 

 no reenactment of creation. Creation — one event ; I have missed out 

 the copula. You can say " was " or " is " at your choice. There is 

 no difference in the two propositions, until an observer is mentioned. 

 In any one observer's world-wide present, for whom creation " was " 

 so many years ago, we can always specify events the observers at 

 which reckon creation as arbitrarily close to " is." 



This situation may be verj difficult to imagine. The difficulty is 

 just that of imagining an infinity of objects in a finite space. (It 

 must be remembered that the dimensions in the direction of motion 

 are reduced by the motion, in accordance with the law of the Lorentz 

 contraction.) But there is no difficulty in describing what we may 

 expect to observe, and this is all that can be demanded. The usual 

 theories put the burden of the trouble on the difficulty of imagining 

 a conceptual curved space. I transfer the difficulty to that of imag- 

 ining an open set of points. This is not really difficult, and in any 

 case it has the advantage of being describable in terms of experience. 



The application of the second law of thermodynamics, invoked in 

 the ordinary proof that the universe is running down, involves the 

 axiom that in any process which occurs in the world it is possible 

 to find another portion of the world unaffected by the process. For 

 to estimate the increase of entropy consequent on the change — to 

 estimate the degree of " running down " involved in the process — it 

 is necessary to compensate the process by reversible changes carried 

 out between the affected part of the universe and the unaffected part. 

 A process must be imagined in which the affected part is restored 

 to its initial state, and the entropy changes thereby occasioned in the 

 orginally unaffected part estimated. It follows that if a process 

 goes on which affects the whole of the universe simultaneously it is 

 impossible to estimate the change of entropy. In such case the proof 



