General Relativity, 221 



correspondence by which the elementary processes in the 

 brain are interpreted may be adjusted in such a way that 

 some of the changes are obscured. 



Again, if we assume that the nature of an electromagnetic 

 field depends on the type o£ fundamental quadratic form 

 which determines the constitutive relations, and thus depends 

 indirectly on a transformation which niters the coefficients 

 of this quadratic form, this d pendence may be a symbol for 

 the relation between physical and mental phenomena instead 

 of giving the influence of gravitation on light as in Einstein's 

 theory. 



Einstein and others have attempted to formulate a set of 

 equations of motion which will coverall physical phenomena; 

 but the present writer does not feel inclined to accept them 

 as final, because in his opinion the true equations of motion 

 should be capable of accounting for the phenomena of life, 

 which after all are the most important physical phenomena. 



To make my position more definite, let us consider one of 

 the methods by which the equations of motion of an electron 

 are obtained in the usual electromagnetic theory. The 

 principle is adopted that at each instant the integral over 

 the electron of the total force on each element must be zero. 

 Now before this principle can be used to write down the 

 equations of motion we must know the design of the electron, 

 and we must know the ivay in which the motions of the 

 different elements are co-ordinated. This co-ordination or 

 organization of the motions of the elements may be repre- 

 sented mathematically by a sequence of infinitesimal trans- 

 formations, by which some of the features of the design are 

 preserved. The design of the electron and the co-ordinated 

 motion of its parts may, perhaps, be specified by a quadratic 

 differential form in four variables, which determines a mapping 

 of the interior of the electron on the interior of a stationary 

 sphere ; but I doubt if this is sufficiently general. A 

 knowledge of this quadratic differential form is necessary 

 then before we can write down the equations of motion of 

 the electron as a whole. What we usually regard as the 

 equations of motion of matter need then to be supplemented 

 by geometrical conditions which specify the design and 

 organization of each elementary portion of matter. Further- 

 more, when this design and organization is assumed to be 

 known, the ordinary equations of motion may be regarded 

 as a consequence of the electromagnetic laws and the above- 

 mentioned principle. 



It must be confessed, however, that this principle does not 



