president's address. 11 



Does the I'ecognition of even such a radical imperfection at the 

 root of the physico-chemical conception really involve its rejection 

 as the characteristic conception of scientific procedure? I do not 

 think that this can be admitted. The objection would hardly be 

 pressed by anyone with regax'd to the use of the idea in physics 

 and chemistry, although, in the last resort, the criticism of the 

 abstract idea of causality as a final principle, is as valid in that 

 sphere as elsewhere. And if in a more obvious and pre-eminent 

 way the mechanical hypothesis breaks down when it is offered as 

 an explanation of vital jDhenomena, it does not do so without 

 giving us splendid proof of its capabilities as a working hypothesis. 

 The search for causes has resulted in the revelation of mechanism 

 upon mechanism in the way of structural organisation; process in 

 multicellular organisms is realised through material parts or 

 organs more and more minute, as far as our means of observation 

 enable us to proceed. Must we halt for ever upon the threshold 

 of intracellular organisation? What is there in that organisation 

 that we should feel obliged there to discard the conception of 

 mechanism, elsewhere so serviceable 1 Do we here enter a new 

 world for the first time 1 Assuredly not. The real obstacle to a 

 mechanical theory of life is not met with at one point more than 

 another, but all along the line. " Vitalistic or teleological inter- 

 pretation," it was urged in last year's address, " is not a method 

 which comes to our rescue when a physical interpretation fails us. 

 In so far as it is valid at all, it is one which is present with us 

 and which urges itself upon us at every staye, forbidding us ever 

 to mistake a 250'^sible mechanical inter-connection of the 

 phenomena of life for the real ground in thought of purposi^'e 

 adaptation." 



In referring to the shortcomings of the attempted jihysico- 

 chemical analysis of living process. Dr. Haldane avers that " we 

 are now far more definitely aware of the obstacles to any advance 

 in this (physico-chemical) direction, and there is not the slightest 

 indication that they will be removed, but rather that, with 

 further increase of knowledge, and more refined methods of 

 physical and chemical investigation, they will only appear more 

 and more difficult to surmount." 



