ii THE STRUCTURE OF MIND 27 



enables us to arrange the actions of the developed human 

 self in a series, the first terms of which are prima facie 

 mechanical in character, i.e. are explicable in terms of the 

 interaction of masses, while the last are prima facie mental, 

 i.e. are explicable only in terms of purpose. Whether this 

 prima facie view can maintain itself to the end or must 

 yield on analysis to the theory that the most developed 

 purpose is the result of a peculiarly complex mechanism 

 is a question which must be taken up again when the exposi- 

 tion of the series is complete. In the meantime we shall 

 deal with mental activity and mental determination as we 

 find them, and make it our business to describe the forms 

 which they assume and the part that they play. By this 

 means we shall trace the development of the mind-function 

 within the self, though we shall leave open the question 

 whether the whole or this development is or is not to be 

 interpreted ultimately in mechanical terms. 



The question thus left open is one of the ultimate nature 

 of causation in the psycho-physical process. We shall 

 nowhere have to challenge the view that a mental state or 

 process implies a bodily state or process as concomitant. 

 We shall only have to ask in the end whether as between 

 these concomitants we are always bound to look to the 

 bodily side for the real explanation of the process. We 

 need not doubt that when I see a ball coming towards me 

 and put up my hand to catch it there is a physiologically 

 continuous process l from the excitement of the retinal cells 

 to the series of muscular adjustments which results in the 

 catch accompanying the mental acts of perception and cona- 

 tion. We need not doubt that when I read a book the 

 train of reflections set up and issuing ultimately perhaps in 

 written and spoken words of my own implies a long series 

 of physical adjustments in cerebral cells. Only, having 

 this circumstance before us, we must insist equally on both 



1 Some psychologists (as Mr. MacDougall, Body and Mind, pp. 288, 

 etc., cf. Sherrington, The Integrative Action of the 'Nervous System, 

 p. 384 ff.) throw doubt on the spatial continuity of the processes involved 

 in some mental operations. I am not qualified to form any judgment 

 on this question. All that is meant in the text is that for the purposes 

 of the present argument no discontinuity need be assumed. 



