444 INTRODUCTION TO PHILOSOPHY OF SCIENCE 



This fact has important implications for a theory of real- 

 ity, since it puts definite limitations on the scope of physical 

 knowledge. Our knowledge of the properties of a body con- 

 sists merely of the responses of various metrical indicators 

 to its presence. Beyond this knowledge cannot go. If one 

 could get the responses of an object to all sorts of devices — 

 scales, clocks, meter sticks, thermometers, etc., — he would 

 know it completely in relation to its environment. All that 

 he could not know would be its "inner un-get-at-able " 

 nature. 1 Hence it turns out that the world of scientific ob- 

 jects becomes not only symbolic of the world of experience 

 but merely a 'shadow' world 2 without the substantiality 

 of the world of everyday objects. It is only such knowledge 

 of that world as we should have of a game of chess if we 

 knew merely the rules of the game and not the nature or 

 appearance of the chessmen, 3 or such knowledge as we should 

 have if we knew only the structural form of the world and not 

 its content. 4 Our conception of the physical world today is 

 essentially hollow. It is merely a system of symbols connected 

 by mathematical equations. Such a scheme, Eddington 

 maintains, is essentially a skeleton, and proclaims its own 

 hollowness. 5 In fact, if anyone knew the method of the physi- 

 cist in advance he would be able to foretell the kind of world 

 which would be revealed through the use of this method. 6 



Such are the data of the speculative problem. What of 

 the inference? It appears that the nature of scientific sym- 

 bols hints at a reality which is non-metrical. The hollow 

 world "can be — nay it cries out to be — filled with something 

 that shall transform it from skeleton into substance, from 

 plan into execution, from symbols into an interpretation of 

 the symbols." 7 A wave is an abstraction which may be filled 

 with a variety of contents; there may be waves of water, 

 waves of air, waves of ether, and waves of probability. 

 Physics shows only that the world is made up of waves, and 



1 Ibid., p. 257. < Ibid., p. 200. 



2 Ibid., p. xiv. 8 New Pathways in Science, p. 313. 



3 Space, Time, Gravitation, p. 184. 6 Nature of the Physical World, p. 271. 



7 New Pathways in Science, p. 314. 



