THE MECHANISM OF NATURE 291 



do with the reality of my freedom; for one who knows nothing, 

 either positively or negatively, about absolute freedom may never- 

 theless be convinced that, as a practical matter, he is free and 

 responsible. 



While we may from premises infer a conclusion, it will not fol- 

 low that we can argue reciprocally and from the conclusion infer 

 the premises. 



Proof that my voluntary acts are arbitrary and not mechanical 

 might prove them free ; but it does not follow that my confidence 

 in my freedom proves that it is arbitrary and not mechanical; for 

 if mechanical means orderly, the only contrasted meaning I can find 

 for the word arbitrary is disorderly. 



When we speak of the reduction of nature to mechanical princi- 

 ples, and when we compare the works of nature to a machine, what 

 do these words mean } 



Our notion of the human contrivances we call machines is clear 

 and definite. A clock is a machine, and so is a steam-engine. The 

 definition of machines in the " Encyclopaedia Britannica " tells us 

 they "produce some useful purpose," and use is the very essence 

 of an artificial machine ; for mechanical toys are not made without 

 a purpose. In common speech a purposeless machine is, so far as 

 may be, a contradiction in terms; and they who find difficulty in 

 reconciling the mechanism of nature, or the mechanism of our 

 minds, with purpose or intention must have some other meaning in 

 mind. To put ourselves in their place, we must try to find out this 

 meaning if we can, for it may be that the assertion that our minds 

 are mechanical will prove to be only another way of saying that they 

 are useful. 



Mechanics divide artificial implements into instruments, struct- 

 ures, and machines. Clocks and locomotives are machines; railroads 

 and bridges are structures; and the wrenches and files of the engi- 

 neer are instruments. While these three classes are not sharply 

 separated, I think they bring out the meaning we are seeking. 

 Machines, instruments, and structures are alike useful, but they 

 are not used in the same way. What the wrench and the bridge 

 were before they were used, that they remain while used and after 

 they have been used, and they are used only so long as they are 



