126 



NATURE 



[June ii, 1903 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications.] 



Psychophysical Interaction. 



Since Nature is read by many people beside physicists 

 and mathematicians, it may be useful to state explicitly 

 that a letter with a diagram, on p. 102, is erroneous and 

 misleading. 



For the same reason it may be desirable to remark dis- 

 tinctly, in opposition to a notion apparently suggested by 

 several previous writers, that guidance or deflection of 

 motion is not in the least contradictory of the principle of 

 the conservation of momentum. For the rest, all the letters 

 of importance which have recently appeared are in accord- 

 ance with my views. " 



Oliver Lodge. 



I HAVE followed with much interest the discussion opened 

 in your columns by Sir Oliver Lodge's recent contention 

 that mind directs but does not create energy. What is 

 aimed at, as I understand it, by this distinction is the 

 reconciliation of the activity and efficiency of mind with 

 the mechanical laws of the conservation of energy and 

 momentum. The distinction itself is, as is well known, 

 as old as Descartes, being designed by him to meet the 

 ■same problem as it presented itself to the thinkers of the 

 seventeenth century. As is also well known, it was 

 immediately disowned by his successors on the ground that 

 guidance or direction of energy by the mind is an inter- 

 ference with the operation of material forces as the physicist 

 is bound to conceive of them not less than the creation of 

 it. Why is it more inconceivable that mind should alter 

 •energy or momentum than that it should interfere in any 

 way whatever with the material world as a closed 

 mechanical system ? While to Sir Oliver Lodge it seems 

 axiomatic that mind cannot produce energy, to others it 

 has seemed equally axiomatic that it cannot resist or control 

 it. It remains, therefore, for those who propose to revive 

 the above distinction as a way of making the relation of 

 mind to matter comprehensible to show by an analysis of 

 the conception of control that the direction of physical 

 energy by the mind is any more intelligible than its creation. 

 Failing this, the problem they have sought to solve by 

 means of this formula only returns in a deeper form. How 

 is mental efficiency in any shape to be reconciled with 

 fundamental mechanical principles? The purpose of this 

 letter is to suggest a form of solution, somewhat different 

 from that of Prof. Ward's in his " Naturalism and 

 Agnosticism," which makes recourse to so ambiguous a 

 ■distinction unnecessary. 



Stated in its most general form, the problem is that of 

 the operation of mind upon matter. Three answers have 

 •stood out owing to the authority of those who at different 

 times have advocated them : — 



(i) It has been held that mind and matter are each in 

 its own sphere effectively operative, but that these spheres 

 .are wholly different. They never touch or intersect. 

 Where there appears to be coincidence, as in knowledge or 

 in the action of one upon the other, this is to be explained 

 (if an explanation is insisted on) as the result of pre- 

 arrangement. Except in the form of the working hypo- 

 thesis of parallelism, no responsible thinker would probably 

 .accept this " dualistic " theory at the present time, and it 

 need not further be considered. 



(2) The second answer is that which explains mental 

 activity as merely apparent. The really active forces are 

 material. Consciousness is merely a by-product, standing 

 to material forces as the steam which is dissipated in the 



-air stands to the steam-engine — a sign of its operation, 

 but itself contributing nothing to its efficiency. This 

 "" materialistic " theory is surrounded by difficulties which 

 this is not the place to discuss, but which the present 

 generation seems to be in the main agreed are insuperable. 



(3) A third view remains which takes up the problem at 

 ..an earlier point, and asks whether our difficulty is not a 



self-made one. If we set out from the existence of mind 



NO. 1754, VOL. 68] 



and matter as two entirely separate substances, there is, if 

 must be admitted, no way in which we can establish any 

 continuity or causality between them. On the other hand, 

 if we reverse this assumption, and regard the conception of 

 two worlds, a physical and a mental, as one that grows up 

 within (it is not said created by) our experience, a way 

 seems opened up out of the difficulty. The conservation 

 of energy and momentum, and the determination of their 

 direction by physical antecedents, are from this point of 

 view conceptions which are forced upon us in our endeavour 

 to interpret to ourselves one side or aspect of our ex- 

 perience — that which we call the mechanical. Within the 

 area so describable they are universal, ultimate, admitting 

 of no exception. But the mechanical is only one side of 

 our experience. Besides mechanical energy there is life. 

 The phenomena of life violate no mechanical law, yet open 

 up to us a new aspect of our world, a new form of 

 " energy." We may, indeed, try to " explain " life as 

 only a more complex mechanism, and this has been a 

 common device since the time of Descartes. But the pre- 

 sent day tendency to recognise here a transitio in aliud 

 genus, and to reject (as leading to confusion) the attempt 

 to explain the fuller, more concrete reality by formulaj 

 applicable only to the more abstract, seems to be founded 

 on a truer insight. What holds of the relation of life to 

 mechanism holds also of the relation of mind to life in 

 general. Here also a new world opens up with laws of 

 its own, no more identifiable with those of matter or 

 organism than the system of mechanical forces which make 

 up the movement of the billiard ball upon the table or the 

 contraction of the muscles in the player's arm is identifiable 

 with his acquired dexterity or his gaming ambition. 



" But how," it may be asked, "does ail this help us? 

 Granted the world of Nature has these different ' sides,' we 

 are no nearer understanding how any one side is connected 

 with another, least of all how the ' world as will and idea ' 

 is connected with the world as matter and energy." It 

 is just here that I wish to invite the physicist who may not 

 have considered the question in this light to make an ex- 

 periment with his ideas which may not hitherto have 

 suggested itself, and when suggested may appear to him 

 as ridiculous as an invitation to vary his outlook upon the 

 universe in the interest of science by standing upon his 

 head. The suggestion is that instead of starting, as prob- 

 ably he has been accustomed to do, from the presupposition 

 that the entirely real and concrete is what is known as the 

 physical world, and that everything else must fall into line 

 as in some sense a product or reflection of it, he should start 

 from his own experience as a whole — his mind and will as 

 it exercises itself in the world of reality in general, in- 

 cluding, of course, other minds and wills — as though this 

 were the primary, most entirely real and concrete fact that 

 he knows, and regard all else as comparatively abstract 

 and secondary. The former view I invite him to consider 

 for the time being as analogous to the old Ptolemaic 

 astronomy, the latter as the Copernican. When he has 

 done so I ask him further to consider whether the operation 

 of mind on matter need any longer constitute the insoluble 

 problem the older hypothesis made of it. Putting aside 

 the question of the relation of our individual minds to the 

 mind of the Creator, the single " real " activity is from this 

 point of view that of a conscious will in presence of a 

 universe which it is its one supreme interest to understand 

 and adapt to its own ends of life and well-being. The 

 condition of such understanding and adaptation is selection 

 and abstraction ; its one supreme law divide et impera. A 

 fundamental division at which developing experience early 

 arrives is that of an inner and an outer — a self and other. 

 A subdivision of the latter, which it is not long in 

 achieving, is into the material other and the mental other— 

 the physical and the social world. In this way the division 

 proceeds, but always into parts of a whole of which we 

 must keep a hold and to which we must ever return 

 wherever the danger threatens of becoming the victim of 

 our own abstractions. Treated as an articulate part of the 

 whole, each field falls into its place in the organism of 

 experience — general philosophy being the attempt to state 

 what that place is ; when hypostatised into an independent 

 reality, still more when mistaken for the whole it leads 

 only to confusion. From the beginning of speculation the 

 front of the offending has here lain with Matter. Philo- 



