224 



DISCOVERY 



Correspondence 



THE PROBLEM OF PERSONALITY 



To the Editor of Discovery 



Sir, 



The correspondence in your columns on the subject 

 of PersonaUty and its basis or bases adds weight to your 

 original suggestion that there was need for classification 

 and collation of the different views on the subject. 



Might I endeavour in the fewest possible words to give 

 the views of a biologist ? In face of the short space at 

 my disposal, I shall be forced to make what appear 

 dogmatic assertions : may I make it clear at the outset 

 that the assertions represent simply my own opinions 

 (although I also think that many, perhaps most, biologists 

 would agree with me), and that I could adduce evidence 

 if space were available ? 



Modern biology, then, is coming to think of the organism 

 as a unitary psycho-physical mechanism ; both ' ' mental 

 and ' ' material ' ' characters are properties of the living 

 substance of which it is composed. Its view is therefore 

 neither idealist nor materialist, but, if you like, monist. 

 It is impossible to alter one function without altering 

 others indirectly ; thus the mental reacts upon the 

 physical, and vice versa. 



In considering the problem of personality, we have to 

 distinguish at the very outset between inherited factors 

 and environmental factors. Both of these may influence 

 the personality. A good example is given, e.g., by worry. 

 Worrying tends to a certain type of so-called neurasthenia. 

 The fact of worrying, however, and its intensity, depend 

 (a) upon the tangible " worries " which confront a man, 

 but also (b) upon the degree of his hereditary predisposi- 

 tion to worry. Circumstances which one man will con- 

 front with equanimity may lead to a nervous breakdown 

 in another. Or, again, phthisis depends (a) on an external 

 factor, the tubercle bacillus, and (b) on a factor which is 

 chiefly hereditary — the degree of resistance to infection. 

 Practically all of us harbour tubercle bacilli ; but in only 

 a comparatively small percentage do they give rise to 

 disease. 



Personality in a similar way is partly dependent upon 

 external, environmental factors — social conditions, in- 

 fection, treatment when young, worry, etc. etcr These 

 factors, however, undoubtedly play a relatively small 

 part in forming personality compared with those wliich 

 are hereditarily determined. 



Here we have to think, so to speak, on several different 

 levels. In the first place, there can be no doubt that the 

 characters of body and mind alike are mainly determined 

 by the hereditary factors or genes contained in the 

 fertilised ovum and revealed to us by the work of Mendel, 

 Bateson, Correns, Morgan, etc. During embrj'onic develop- 

 ment, however, these give rise, inter alia, to the ductless 

 glands, and thenceforth these are entrusted with a very 

 important share in the regulation of growth, chemical 

 processes, nervous reactions, etc. etc. There can be no 



doubt that these glands, once formed, do exert pronounced 

 efiects upon the quality and types of the personality. 

 Dr. Herman has been hasty in many of liis generahsations, 

 as well as neglectful of everything but the ductless gland 

 system ; but he has done good work in promoting dis- 

 cussion, and in making the public realise that personality 

 is only a name for a balance of elements in the organism, 

 much of wliich is determined by the ductless glands. 

 Numerous other chemical processes also occur which 

 . must react on the glands and brain and so affect per- 

 sonality. 



Finally, we have the brain and the rest of the nervous 

 system, whose development is also determined by heredi- 

 tary factors in the germ-plasm. There is again no doubt 

 but that inherited variations in general brain-type, and 

 correspondingly in mind-type, do occur. For instance, 

 some nervous systems appear to be more easily excitable 

 than others ; or, again, some minds make associations 

 more readily, others less readily — this difference is 

 probably at the bottom of the difference between the 

 "introvert" and "extrovert" types of the modem 

 psychologist. Many other general tendencies and special 

 aptitudes of mind (e.g. music) are undoubtedly hereditary. 

 Finally, once the brain and mind have been formed in 

 development, they may react upon the rest of the nervous 

 system and through it upon the ductless glands. 



We may sum up our conclusions in diagrammatic form, 

 thus : 



i(i) Hereditary factors 

 (genes) in germ-plasm. 

 These give rise to : 



(2a) Chemical processes 

 of ductless glands. 



(26) Other chemical pro- 

 cesses within the body. 



(zc) Nervous system and 

 brain, with associated 

 mind (psycho-neural 

 J mechanism) . 



This last may react upon 

 (2a) and (26). 

 \ B. Environmental. 



/A. Inherited 



Factors 

 affecting 

 personality 



It is of course for certain purposes possible to tliink of 

 the organism on a purely mechanical, or a purely chemical, 

 or a purely mental basis. Any such view, however, is 

 bound to be partial. 



Mechanical, chemical, electrical, mental processes all 

 occur within the organism ; the organism can only be 

 considered as a whole ; and in considering any complex 

 property of the organism as a whole, such as personality, 

 we cannot neglect any of these various factors. The 

 problem is extremely complex, but does not present any 

 logical difficulty if looked at from the monistic angle I 

 have indicated. 



Yours, etc., 



J. S. Huxley. 

 New College, Oxford. 

 June 6, 1922. 



