8 president's address. 



The necessity for a recognition of the general principle of 

 deterixiination by ends as a synthetic and unifying principle of 

 interpretation, has inspired at various epochs the advocates of 

 what is called "vitalism" in biology. The older vitalism, of which it 

 has been well said that it was merely " mechanism misunderstood," 

 like the old theological "design argument," has served to bring 

 " teleology " into disrepute during the greater part of the century. 

 To disparage this much abused principle has been a shibboleth of 

 not a little of the later biological literature of the century. It is 

 to modern philosophical criticism that we are indebted for what 

 I believe to be a clearer insight into the relative validity of the 

 two principles of cause and purpose respectively, as applied to 

 the interpretation of phenomena. Through it we may learn that 

 the recognition of purpose in the interpretation of nature does 

 not necessarily involve the intrusion of a new extraneous, super- 

 physical form of "vital" energy. This would be "mechanism 

 misunderstood." But through it we also learn to discard the 

 widely prevalent view that the principle of mechanical causation, 

 which forms the governing conception of physics end chemistiy 

 as scientific disciplines, is therefore to be regarded as the sole and 

 only synthetic principle by which we can connect phenomena in 

 the unity of a single system. 



Having devoted a considerable portion of my former address 

 to the attempt to set forth the position just outlined, I should 

 have thought it unnecessary to return to it on the present occasion 

 but for the circumstance that in the interval there has appeared 

 in the issue of the "Nineteenth Century' " for September, 1898, 

 a contribution towards the discussion of this very question of 

 " vitalism " versus "mechanism." A consideration of this may, 

 on the present occasion, be deemed neither out of place nor wholly 

 unprofitable. 



The article in question is from the pen of my friend Dr. J. S. 

 Haldane, Lecturer on Ph3^siology in the University of Oxford, 

 whose previous utterances on the same subject, together with his 

 very high reputation as an experimental physiologist, entitle him 



