THE EXTERNAL WORLD 87 



same as it was. Thus the difficulty, if it exists, has at 

 least not been rightly stated. 



We will now make a new start, adopting a different 

 method. Instead of inquiring what is the minimum of 

 assumption by which we can explain the world of sense, 

 we will, in order to have a model hypothesis as a help for 

 the imagination, construct one possible (not necessary) 

 explanation of the facts. It may perhaps then be possible 

 to pare away what is superfluous in our hypothesis, 

 leaving a residue which may be regarded as the abstract 

 answer to our problem. 



Let us imagine that each mind looks out upon the 

 world, as in Leibniz's monadology, from a point of view 

 peculiar to itself ; and for the sake of simplicity let us 

 confine ourselves to the sense of sight, ignoring minds 

 which are devoid of this sense. Each mind sees at each 

 moment an immensely complex three-dimensional world ; 

 but there is absolutely nothing which is seen by two 

 minds simultaneously. When we say that two people 

 see the same thing, we always find that, owing to 

 difference of point of view, there are differences, how- 

 ever slight, between their immediate sensible objects. (I 

 am here assuming the validity of testimony, but as we 

 are only constructing a possible theory, that is a legitimate 

 assumption.) The three-dimensional world seen by one 

 mind therefore contains no place in common with that 

 seen by another, for places can only be constituted by the 

 things in or around them. Hence we may suppose, in 

 spite of the differences between the different worlds, that 

 each exists entire exactly as it is perceived, and might be 

 exactly as it is even if it were not perceived. We may 

 further suppose that there are an infinite number of such 

 worlds which are in fact unperceived. If two men are 

 sitting in a room, two somewhat similar worlds are 



