LIVING THINGS AND MACHINES 123 



Professor Duncan 1 says that "any discussion of 

 ether leads out upon the high road to incredulity. 

 A thing," he proceeds, "must be defined by its 

 properties and the properties of the ether are for 

 the most part negative ; so negative, indeed, are 

 they, that when one says boldly that we cannot see 

 ether, hear it, taste it, smell it, exhaust it, weigh it, 

 or measure it, one feels timid that sane-minded peo- 

 ple will meet these negative qualities of our ether 

 by a decided negation of belief in its existence. 

 But the fact of the matter is that if this thing 

 'ether' is not visible to the eye of sense it is visible 

 to the eye of the mind which is much less liable to 

 err." And he proceeds to show the grounds on 

 which the ether is believed in, purely on account 

 of its manifestations and not because it has been 

 made obvious in itself to any of our senses aided 

 or unaided. 



If then the vitalistic explanation is verbal only 

 so also is the theory of gravitation and so the exist- 

 ence of the ether. 



It shall be left to a distinguished physiologist 

 to have the last word on this subject in the present 

 chapter. Dr. Haldane 2 says : " It is frequently 

 urged that vitalism amounts to nothing more than 

 the mere assertion that a physico-chemical explana- 



1 The New Knowledge, 1907, p. 3. 



2 Loc. supra cit. 



