SPACE, TIME 303 



events; events in this world simply do not occur that way. 

 An earlier instant does not cause a later instant; rather, an 

 earlier event causes a later event. Hence with the elimina- 

 tion of events from time there is no longer any obstacle 

 to the view that time is reversible. Time becomes a series, 

 and a series has no unique directional features. 



SPACE-TIME 



In conclusion, brief reference may be made to the modifi- 

 cations which have been introduced into the scientific notion 

 of space and time through the discoveries which eventuated 

 in the theory of relativity. From the limited point of view 

 of the treatment in this chapter the differences between the 

 two views may be explained in terms of difficulties which 

 arise in connection with the operational derivation from 

 empirical space and time. It has already been suggested 

 that Newtonian time and Euclidean space are constructs. 

 By this is meant that they do not describe obvious features 

 of nature but are derived from them by certain logical 

 techniques. Immediately the question arises as to whether 

 the techniques are legitimate. There are two ways of answer- 

 ing this question. One is to examine the techniques them- 

 selves, and ascertain the assumptions upon which they are 

 based. This is the more difficult task, since the techniques 

 are not certainly known, and most of the assumptions are 

 implicit. The second way is to employ the ordinary tech- 

 niques of verification; Newtonian time and Euclidean space 

 evidently function not only as constructs but as hypotheses 

 as well, hence their adequacy may be determined by draw- 

 ing the implications from them and subjecting these to 

 empirical corroboration. If the predicted consequences are 

 not verified, presumably the techniques of derivation have 

 not been correctly employed, and abandonment or revision 

 of the hypotheses is necessary. This is the easier task, but 

 it unfortunately does not tell us precisely in what respect 

 the hypotheses are wrong, nor precisely where the error in 

 operation has been committed. 



