DAVID HUME 69 



and sensory nerves. All that we immediately 

 perceive can only be sensory disturbances 

 of some kind, from which we infer the exist 

 ence of the physical reality outside. This is a 

 necessary, but also a fatal admission : for what 

 right have we to draw such an inference? 

 Absolutely none, as Bishop Berkeley first 

 pointed out. We have no right even to call 

 our sensations impressions, or to regard 

 ourselves as anything more than a stream of 

 sensations. The appearance of a sensible 

 world, with our bodies present in it, can be 

 nothing but an appearance due to the manner 

 in which the sensations group themselves. 

 The appearance of substantiality or of cause 

 and effect can be due to nothing else but the 

 mysterious fact that certain sensations are 

 associated together or follow one another in 

 a certain order. Such was the reasoning of 

 David Hume ; and his inferences follow 

 inevitably if we start with the provisional 

 assumption that the physical world as science 

 represents it to us has absolute reality. If it 

 has, then we cannot possibly know it ; and all 

 our supposed knowledge is nothing but the 

 illusion which Hume described. 



B* 



