SENSE-DATA AND PHYSICS 167 



the matter in our immediate neighbourhood ; e.g. the 

 visual appearance of a distant object is a function of the 

 light-waves that reach the eyes. This leads to confusions 

 of thought, but offers no real difficulty. 



One appearance, of a visible object for example, is not 

 sufficient to determine its other simultaneous appearances, 

 although it goes a certain distance towards determining 

 them. The determination of the hidden structure of a 

 thing, so far as it is possible at all, can only be effected by 

 means of elaborate dynamical inferences. 



X. TIME 1 



It seems that the one all-embracing time is a con 

 struction, like the one all-embracing space. Physics 

 itself has become conscious of this fact through the dis 

 cussions connected with relativity. 



Between two perspectives which both belong to one 

 person s experience, there will be a direct time-relation of 

 before and after. This suggests a way of dividing history 

 in the same sort of way as it is divided by different 

 experiences, but without introducing experience or any 

 thing mental : we may define a &quot; biography &quot; as every 

 thing that is (directly) earlier or later than, or simul 

 taneous with, a given &quot; sensibile.&quot; This will give a series 

 of perspectives, which might all form parts of one person s 

 experience, though it is not necessary that all or any of 

 them should actually do so. By this means, the history 

 of the world is divided into a number of mutually exclusive 

 biographies. 



1 On this subject, compare A Theory of Time and Space, by Mr. 

 A. A. Robb (Camb. Univ. Press), which first suggested to me the views 

 advocated here, though I have, for present purposes, omitted what is 

 most interesting and novel in his theory. Mr. Robb has given a sketch 

 of his theory in a pamphlet with the same title (Heffer and Sons. 

 Cambridge. 1913). 



