'54 



What we call the different appearances of the same thing 

 to different observers are each in a space private to the 

 observer concerned. No place in the private world of 

 one observer is identical with a place in the private world 

 of another observer. There is therefore no question of 

 combining the different appearances in the one place ; 

 and the fact that they cannot all exist in one place affords 

 accordingly no ground whatever for questioning their 

 physical reality. The " thing " of common sense may in 

 fact be identified with the whole class of its appearances 

 where, however, we must include among appearances 

 not only those which are actual sense-data, but also 

 those " sensibilia," if any, which, on grounds of con- 

 tinuity and resemblance, are to be regarded as belonging 

 to the same system of appearances, although there 

 happen to be no observers to whom they are data. 



An example may make this clearer. Suppose there are 

 a number of people in a room, all seeing, as they say, the 

 same tables and chairs, walls and pictures. No two of 

 these people have exactly the same sense-data, yet there 

 is sufficient similarity among their data to enable them 

 to group together certain of these data as appearances of 

 one " thing " to the several spectators, and others as 

 appearances of another " thing." Besides the appear- 

 ances which a given thing in the room presents to the 

 actual spectators, there are, we may suppose, other 

 appearances which it would present to other possible 

 spectators. If a man were to sit down between two 

 others, the appearance which the room would present to 

 him would be intermediate between the appearances 

 which it presents to the two others : and although this 

 appearance would not exist as it is without the sense 

 organs, nerves and brain, of the newly arrived spectator, 

 still it is not unnatural to suppose that, from the position 



