HOW THE BRAIN THINKS 



cession of electrical impulses from a dynamo, for 

 example, will make the frog's legs twitch rhyth- 

 mically, just as do the salt solutions. If we use 

 old William of Occam's razor that we shall cut 

 out all needless assumptions or suppositions what- 

 soever then we shall say that the electric current 

 from a machine and the nervous disturbance gen- 

 erated by the solution are identical. And as the 

 twitch aroused by dipping the end of the nerve in a 

 salt-bath is exactly the same as occurs when the 

 frog is alive, then we must say that a nerve current, 

 or nerve-wave, is electrical in character. 



If this frightens no one, then we may add that the 

 excitation which moves the legs of a frog and that 

 which winks your eye or twirls your flying fingers 

 over the piano-keys is absolutely the same and is 

 due to the same cause. 



And now for the final plunge into what Huxley 

 satirically called the dank morasses of materialism. 

 You are seated at the piano; the reflection of a 

 jumble of dots on the page of music falls upon the 

 retina of your eye; their position, size, and shape 

 are telegraphed to your brain; thence comes a 

 series of orders to arms and fingers ; you are play- 

 ing a Chopin nocturne. Providing you have spent 

 months or years in patient and often painful prac- 

 tice, you can do all this and be talking to a friend 

 at the same time, hardly conscious either of the 



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