426 SCIENCE PROGRESS 



We have to regard the stimulus as delivered upon certain dots 

 at one end, and transmitted to a further group of dots at the 

 remote end. Is it more intelligible that a stimulus, entering by 

 different doors and departing by the same door, should be 

 transmitted by ordinary mechanical principles, or that certain 

 dots in the middle should suddenly assume a ghostly agitation, 

 and carry the diverging mechanical impulses to a common exit? 

 Vitalism affirms the negation of law ; a thing unknown in the 

 experience and history of man. Vitalism, affirming that the 

 belief of its opponents is inconceivable, sets up an alternative 

 that is far more inconceivable. 



It has not, of course, been possible to mention all the main 

 arguments of both sides in the present article. It is indeed only 

 desired to give an indication of the nature of the arguments 

 used. Vitalistic writers are far more numerous than mechanistic 

 writers ; for vitalism has a strong natural appeal to the average 

 mind. Mechanism is almost limited to biologists, and is over- 

 whelmingly supported only by physiologists, with a few stray 

 philosophers. Consequently there are many shades of opinion 

 and argument in the vitalist camp ; there are many vitalisms, 

 but only one mechanism. Dr. C. A. Mercier has endeavoured 

 to defend an agnostic view, affirming that the problem is 

 insoluble ; but since he presents a number of arguments 

 suggesting a vitalistic solution, he must be reckoned as inclined 

 at all events to recede from the absoluteness of his agnosticism- 

 Reverting once more to the billiard balls, it is quite clear that 

 either some new motion is created out of nothing (in which case 

 vitalism would be true), or it is not (in which case mechanism 

 would be true). To affirm that we can never know the truth is 

 to set limits on the advance of nervous physiology, and to deny 

 that we shall ever be able to penetrate into the nature of nervous 

 processes. Seeing how far we have already gone towards the 

 penetration of such processes, especially during the last few 

 years, and how rapid the progress has been, there seems no 

 more justification for saying that we have at length reached a 

 limit than there would be for making the same statement about 

 the construction of naval armaments. 



The philosopher regards science as an expanding sphere of 

 light set in the midst of infinite darkness. Wherever there is 

 light we find all reduced to law and uniformity ; wherever there 

 is darkness the popular imagination has at all times peopled the 



