Ill ON THE PHYSICAL BASIS OF LIFE 157 



"All knowledge is experience of facts acquired by the senses. 

 The traditions of older philosophies have obscured our experi- 

 ence by mixing with it much that the senses cannot observe, 

 and until these additions are discarded our knowledge is impure. 

 Thus metaphysics tell us that one fact which we observe is a 

 cause, and another is the effect of that cause ; but, upon a rigid 

 analysis, we find that our senses observe nothing of cause or 

 effect : they observe, first, that one fact succeeds another, and, 

 after some opportunity, that this fact has never failed to follow 

 that for cause and effect we should substitute invariable suc- 

 cession. An older philosophy teaches us to define an object by 

 distinguishing its essential from its accidental qualities : but 

 experience knows nothing of essential and accidental ; she sees 

 only that certain marks attach to an object, and, after many 

 observations, that some of them attach invariably whilst others 



may at times be absent As all knowledge is relative, the 



notion of anything being necessary must be banished with other 

 traditions." l 



There is much here that expresses the spirit of 

 the " New Philosophy," if by that term be meant 

 the spirit of modern science ; but I cannot but 

 marvel that the assembled wisdom and learning 

 of Edinburgh should have uttered no sign of 

 dissent, when Comte was declared to be the 

 founder of these doctrines. No one will accuse 

 Scotchmen of habitually forgetting their great 

 countrymen ; but it was enough to make David 

 Hume turn in his grave, that here, almost within 

 ear-shot of his house, an instructed audience 

 should have listened, without a murmur, while his 

 most characteristic doctrines were attributed to a 



1 The Limits of Philosophical Inquiry, pp. 4 and 5. 



