iv DESCARTES' DISCOURSE ON METHOD 187 



supposes his waterwork Diana to be moved. But 

 we may go further, and inquire whether our 

 volition, in what we term voluntary action, ever 

 plays any other part than that of Descartes' 

 engineer, sitting in his office, and turning this 

 tap or the other, as he wishes to set one or 

 another machine in motion, but exercising no 

 direct influence upon the movements of the 

 whole. 



Our voluntary acts consist of two parts : firstly, 

 we desire to perform a certain action; and, 

 secondly, we somehow set a-going a machinery 

 which does what we desire. But so little do we 

 directly influence that machinery, that nine-tenths 

 of us do not even know of its existence. Suppose 

 one wills to raise one's arm and whirl it round. 

 Nothing is easier. But the majority of us do not 

 know that nerves and muscles are concerned in 

 this process ; and the best anatomist among us 

 would be amazingly perplexed, if he were called 

 upon to direct the succession, and the relative 

 strength, of the multitudinous nerve-changes, 

 which are the actual causes of this very simple 

 operation. So again in speaking. How many of us 

 know that the voice is produced in the larynx, 

 and modified by the mouth ? How many among 

 these instructed persons understand how the 

 voice is produced and modified ? And what living 

 man, if he had unlimited control over all the 

 nerves supplying the mouth and larynx of another 



