RELATION OF PHYSIOLOGY TO PHYSICS. 9 



sufficient to enable us to understand physiological 

 phenomena. But if so, we need not sit down in despair, 

 for we can look for other working conceptions. Are we 

 justified in doing this ? I think we are. 



There is a prevalent popular idea that the world as 

 presented to us under the conceptions of physics and 

 chemistry is more than our own imperfect conception of 

 reality, and corresponds completely with reality itself. 

 Philosophy has shown us, however, that this idea must 

 be erroneous ; for if it were correct, knowledge of such 

 a world would be impossible. This was first clearly 

 pointed out almost two hundred years ago in this city 

 by one of the greatest of Irishmen, George Berkeley, at 

 that time a Fellow of Trinity College. 1 The lesson 

 taught by Berkeley, Hume, and their successors is not 

 that physical science is of less value than it appears to 

 be, but that its fundamental hypotheses are only working 

 hypotheses, applicable only so far as they successfully 

 fulfil their purpose. Each different science is thus free 

 to employ whatever working hypotheses may prove 

 most useful in interpreting the order of phenomena with 

 which it deals. We are thus perfectly justified in seeking 

 to find a conception of life which will serve as a better 

 working hypothesis than that of life as a physico-chemical 

 process. 



I venture to think that the conception we are in search 

 of lies very near to hand, and is indeed in common use, 

 though in a form which has hitherto been too ill-defined 

 for deliberate scientific employment. It is simply the 

 conception of the living organism, which stands, or 

 ought to stand, in the same relation to biology as the 

 1 Treatise concerning the Principles of Human Knowledge, 1710. 



