ESSAY-REVIEWS 135 



defines the issue between mechanism and vitalism. Mechanism regards the 

 organism as nothing more than a connected collection of physical and chemical 

 processes ; vitalism assumes an extra factor that is not physicochemical. This 

 issue is clearly defined and remains so however uncertain the nature of this extra 

 factor and however vitalists may differ among themselves. To believe that 

 organism = chemistry + physics 4- X is vitalism. X may be regarded as un- 

 known or described in any way whatever — it is vitalism in all cases. Mechanism 

 deletes the X. The problem can be defined with certainty as X or no X ; with 

 any attempt at solution certainty disappears. 



The discussion is fundamental and far-reaching. Mind and consciousness 

 appear in the living thing. Psychology and, through it, the whole range of 

 thought thus become deeply involved. "Any fact," writes Sir Martin Conway, 

 " may be chosen as the centre of all knowledge," and " any study, if pursued to 

 the end, leads on to all other studies." But some parts of knowledge are more 

 intimately connected with the whole than others — as London is a better centre for 

 exploring or knowing the world than the Arctic wilds. So the mechanico- 

 vitalistic issue, with all its implications and lines of research, bears with particular 

 immediacy on the problems presented to thought. There is, no doubt, a close 

 connection between this immediacy of bearing and the difficulty of the problem. 

 It is improbable that the nature or even the simple existence or non-existence of 

 so momentous an X will be disclosed to simple inspection. Neither is it sur- 

 prising to discover that the more prolonged the research the less soluble the 

 problem appears. Mechanism and vitalism have not yet composed their dif- 

 ferences. It may not be desirable that humans should settle their greater 

 problems promptly ; it is quite certain that they cannot. 



Mechanism begins with the obvious plenty of chemistry and physics in the 

 organism. It becomes more and more confident as it discovers more and more 

 physico-chemico mechanism. It tends, by an almost inevitable mistake, to 

 suppose that the more complete the mechanism the less the room for an extra- 

 mechanical agency. It commits itself to such statements as that in the work that 

 prompted this discussion, " As soon as we can show that a life phenomenon 

 obeys a simple physical law there is no longer any need for assuming the action 

 of non-physical agencies." Imagine an observer on a distant planet who can 

 observe our railway trains but cannot perceive the humans who direct them. 

 He would see the working of the locomotive without noticing the driver. This 

 illustrates the vitalistic notion of the organism, though all such illustrations are, of 

 course, crude. He could interpret the movements of the trains very thoroughly 

 through physicochemical processes. The machinery of the engine would seem 

 self-explanatory ; the burning of the coal operating on the wheels through the 

 drive of the piston propelled by expanding steam would present a purely physico- 

 chemical circuit— as it actually is. The shovelling of the coal into the furnace, 

 if he could observe the motions of the shovel, might strike him as curious, but he 

 would probably conclude that this mechanical causation was beyond the limits of 

 observation— just as the mechanist has constantly to suppose that other chemical 

 or physical processes lie beyond those he can observe. The more this observer 

 studied railway affairs the more impressed he would become with their mechanical 

 nature. He would note that trains started from definite spots at definite times, 

 pursued definite routes at definite rates and had definite stops. In the apparent 

 absence of intelligent agents he would be increasingly impressed by the " clock- 

 work" aspect, and more and more inclined to describe the whole railway system 

 as a mechanism pure and simple. He would tend, in fact, to think, like the 



