26o SCIENCE AND IMMORTALITY 



It must be remembered that only a small fraction 

 of brain is intellectual in function, and it is 

 probable that mental ability depends more on the 

 architectural or textural arrangement of the cells 

 and their special molecular activity than upon 

 their total bulk and weight. 



The brain, then, is in some way and in some 

 sense the organ of thought ; thought is in some 

 way and in some sense dependent on its structural 

 integrity and functional activity ; and yet it is 

 impossible to find the causal connection, and it 

 may well be doubted whether the relationship is 

 causal at all. How can movements or conditions 

 of material atoms, or, if you will, of ethereal 

 vortices, produce sensation and conscious thought ; 

 and why should the production be limited to the 

 special molecular combinations of the cells of the 

 brain ? Waves of ether of a certain length break 

 on the retina of the eye and cause its molecules to 

 vibrate in new ways, and the molecular disturbance 

 spreads up the optical nerve to certain brain-cells 

 and we have consciousness of red. But why have 

 we consciousness of red ? The waves have no 

 colour, the molecular agitations have no colour ; 

 why, then, do we see red ^ By altering the length 

 of the wave, again, we can alter the colour ; but 

 what has length to do with colour } Colour is not 

 fast, or slow, or long, or short. So with sound. 



