A SURVEY OF THE PROBLEM OF VITALISM 423 



only remaining alternative, and therefore necessarily the true 

 explanation. 



This argument is met in a variety of ways. Many physio- 

 logists, such as Loeb and Schafer, have endeavoured to show 

 that the events alleged to be inexplicable by mechanistic means 

 are not in the least inexplicable. In the next place it has been 

 urged that the logic of per exclusionem is erroneous : the whole 

 method is impugned. It is pointed out that it is impossible to 

 know and to marshal all conceivable mechanistic explanations ; 

 that such a proceeding demands an enormously greater know- 

 ledge of nervous physiology than we possess : further, that 

 even though we should succeed in exhausting the list of 

 mechanistic possibilities, the attempt to disprove them is a 

 failure. It is the less necessary for me to dilate upon this 

 subject, inasmuch as I dealt with it at length in this Review 

 two years ago. The opinion that my criticism of vitalistic logic 

 was unanswerable has been borne out by the fact that neither 

 Driesch nor any of his disciples have ever attempted to answer 

 it. More recently I have pointed out that the per exclusionem 

 logic was used by Lamarck and man}' others to prove the 

 existence of a subtle nervous fluid which raced in canals up 

 and down the nervous system. I took the further opportunity 

 of issuing a challenge to vitalists to defend the logic of their 

 position against the heavy preponderance of adverse arguments 

 and opinions ! ; but I think it may safely be assumed that they 

 will not venture to take it up. 



Surely under any principle of per exclusionem the vitalistic 

 hypothesis would be the first to be excluded. Take, for 

 instance, the famous instance of Driesch : " My brother is 

 seriously ill": " Mon frere est severement malade": " Mein 

 Bruder ist ernstlich erkrankt." The utterance of any of these 

 sentences produces very different stimuli to the auditory nerve 

 of a listener. Yet his resulting activity will be the same. If 

 the whole brain and nervous system is a mere piece of 

 mechanism, how can such widely different stimuli set up 

 identical effects ? Supposing, however, the sentence was " My 

 mother is seriously ill," the stimulus would be very nearly the 

 same as in the first case, but the effects would be wholly 

 different. Let us refer once again to the analogy of the 

 billiard balls. 



1 Vide my Introduction to Lamarck's Zoological Philosophy (Macmillan). 



