THE EXTERNAL WORLD 77 



conclusive. It is extraordinarily difficult to see just 

 what the arguments prove ; but if we are to make any 

 progress with the problem of the external world, we 

 must try to make up our minds as to these arguments. 



A table viewed from one place presents a different 

 appearance from that which it presents from another 

 place. This is the language of common sense, but this 

 language already assumes that there is a real table of 

 which we see the appearances. Let us try to state what 

 is known in terms of sensible objects alone, without any 

 element of hypothesis. We find that as we walk round 

 the table, we perceive a series of gradually changing 

 visible objects. But in speaking of " walking round the 

 table," we have still retained the hypothesis that there is 

 a single table connected with all the appearances. What 

 we ought to say is that, while we have those muscular 

 and other sensations which make us say we are walking, 

 our visual sensations change in a continuous way, so that, 

 for example, a striking patch of colour is not suddenly 

 replaced by something wholly different, but is replaced 

 by an insensible gradation of slightly different colours 

 with slightly different shapes. This is what we really 

 know by experience, when we have freed our minds from 

 the assumption of permanent " things ' with changing 

 appearances. What is really known is a correlation of 

 muscular and other bodily sensations with changes in 

 visual sensations. 



But walking round the table is not the only way of 

 altering its appearance. We can shut one eye, or put on 

 blue spectacles, or look through a microscope. All these 

 operations, in various ways, alter the visual appearance 

 which we call that of the table. More distant objects 

 will also alter their appearance if (as we say) the state of 

 the atmosphere changes if there is fog or rain or sun- 



