THE RELATION OF MIND AND BODY 1 



By J. S. HALDANE, M.D., LL.D., F.R.S., 



Fellow of New College and Reader in Physiology, University of Oxford 



From our everyday standpoint a man or higher animal is a 

 personality consciously and purposively controlling, with 

 a certain amount of success, a surrounding physical environ- 

 ment. On closer examination, however, this conception appears 

 unsatisfactory : for the reactions between his body and the 

 environment are apparently physical and chemical in nature : the 

 body itself is apparently part of the physical and chemical world ; 

 the changes within it are apparently physical and chemical 

 changes, no break being noticeable indicative of any point at 

 which they are controlled by an independent mind or soul. Con- 

 sciousness seems, therefore, to be nothing but an accompaniment 

 of physical and chemical changes within the body. 



The facts on which this conclusion depends appear at first 

 sight to be unassailable and to become more and more cogent 

 with every year of advance in physiological knowledge. Psy- 

 chologists thus tend to be driven into the position which has 

 come to be known as "parallelism " or "epiphenomenalism." 



It is important to point out, at the outset of the discussion, 

 that if once we admit that the living body, whatever its pecu- 

 liarities, either forms part of or exists in a real physical world 

 of matter and energy, we are inevitably committed to the con- 

 clusion just indicated : for we can proceed to demonstrate 

 experimentally that the admitted physical and chemical con- 

 ditions determine all bodily activity, conscious or unconscious : 

 we can trace all perception and memory to the action of physical 

 stimuli ; and we can show that the working of the brain depends 

 on physical and chemical conditions. Cut off the oxygen supply 

 to the brain even for a few seconds and all evidence of con- 

 sciousness disappears completely, only reappearing again if 



1 A contribution, with some additions, to a discussion in the Physiological 

 Section of the British Association meeting at Dundee, 1912. 



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