THE FACTS OF SCIENCE 63 



the real world, and yet we can see how conditioned and 

 limited it would be by the range of his particular telephone 

 subscribers and by the contents of their messages. 



So it is with our brain ; the sounds from telephone 

 and phonograph correspond to immediate and stored 

 sense-impressions. These sense-impressions we project 

 as it were outwards and term the real world outside our- 

 selves. But the things-in-themselves which the sense- 

 impressions symbolise, the " reality," as the metaphysicians 

 wish to call it, at the other end of the nerve, remains 

 unknown and is unknowable. Reality of the external 

 world lies for science and for us in combinations of form 

 and colour and touch — sense-impressions as widely diver- 

 gent from the thing " at the other end of the nerve " as 

 the sound of the telephone from the subscriber at the 

 other end of the wire. We are cribbed and confined in 

 this world of sense-impressions like the exchange clerk 

 in his world of sounds, and not a step beyond can we 

 get. As his world is conditioned and limited by his 

 particular network of wires, so ours is conditioned by our 

 nervous system, by our organs of sense. Their peculiarities 

 determine what is the nature of the outside world which 

 we construct. It is the similarity in the organs of sense 

 and in the perceptive faculty of all normal human beings 

 which makes the outside world the same, or practically 

 the same, for them all.-^ To return to the old analogy, it 

 is as if two telephone exchanges had very nearly identical 

 groups of subscribers. In this case a wire between the 

 two exchanges would soon convince the imprisoned clerks 

 that they had something in common and peculiar to them- 

 selves. That conviction corresponds in our comparison 

 to the recognition of other consciousness. 



% 1 2. — Outside and Inside Myself 



We are now in a position to see clearly what is meant 

 by " reality " and the " external world." Any group of 



^ Not exactly the same, for the range of the organs of sense and the powers 

 of perception vary somewhat with different individual men, and probably 

 enormously, if we take other life into account. 



