THE LAWS OF MOTION 321 



with continual reservation. Like so many other features 

 of mechanism it cannot be dogmatically asserted to hold 

 for all corpuscles, but it may in itself flow from the con- 

 stitution we postulate for the ether and the structures we 

 assume for the various types of gross " matter." 



^ 15. — Criticisvi of tJie Newtonian Laws of Motion 



Before we close our discussion of the laws of motion 

 it is only just to the reader to state that the method 

 adopted differs widely from the customary physical treat- 

 ment ; and in deference to the authority on which that 

 treatment is based some comparison and criticism seems 

 called for. We have already dealt with the current 

 definitions of force, matter, and mass, and shown reasons 

 for rejecting them as involving metaphysical obscurity. 

 When, therefore, we come across these terms in the state- 

 ment of the laws of motion we must endeavour to inter- 

 pret them in our own sense. To the reader on first 

 examination the Newtonian statement of the laws of 

 motion may seem much simpler than that of the present 

 chapter. They are stated generally of bodies, and appear 

 to describe the mechanism under which all bodies move, 

 and therefore presumably describe the motion of the 

 whole range of corpuscles from ether-element to particle. 

 Now this loses sight of what the present writer thinks a 

 very important possibility, namely, that not only special 

 modes of motion, but much of the mechanism which 

 describes the action of sensible bodies, will be found 

 ultimately to be involved in some wide-reaching concep- 

 tion of ether and atom. It is not logically satisfactory to 

 describe one mechanism by another of equal complexity ; 

 and we must hope to ultimately conceptualise an ether 

 from the simple structure of which several of the laws of 

 motion postulated for particles of gross " matter " may 

 directly flow. Remembering these points, we now turn 

 to the version of the Newtonian laws given by Thomson 

 and Tait.^ 



^ A Treatise on Natural Philosophy, part ii. pp. 241-7. The writer will not 

 admit that he is second to any one in his admiration for the genius of Newton, 



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