xii INTRODUCTION 



— an incarnate protest against Berkleian subjectivism. 

 It makes all the difference in the world whether the 

 paper before me is poised as it were on a swarm of flies 

 and sustained in shuttlecock fashion by a series of tiny 

 blows from the swarm underneath, or whether it is sup- 

 ported because there is substance below it, it being the 

 intrinsic nature of substance to occupy space to the exclu- 

 sion of other substance; all the difference in conception 

 at least, but no difference to my practical task of writing 

 on the paper. 



I need not tell you that modern physics has by deli- 

 cate test and remorseless logic assured me that my sec- 

 ond scientific table is the only one which is really there — 

 wherever "there" may be. On the other hand I need 

 not tell you that modern physics will never succeed in 

 exorcising that first table — strange compound of external 

 nature, mental imagery and inherited prejudice — which 

 lies visible to my eyes and tangible to my grasp. We 

 must bid good-bye to it for the present for we are about 

 to turn from the familiar world to the scientific world 

 revealed by physics. This is, or is intended to be, a 

 wholly external world. 



"You speak paradoxically of two worlds. Are they 

 not really two aspects or two interpretations of one and 

 the same world?" 



Yes, no doubt they are ultimately to be identified 

 after some fashion. But the process by which the ex- 

 ternal world of physics is transformed into a world of 

 familiar acquaintance in human consciousness is outside 

 the scope of physics. And so the world studied accord- 

 ing to the methods of physics remains detached from 

 the world familiar to consciousness, until after the 

 physicist has finished his labours upon it. Provisionally, 

 therefore, we regard the table which is the subject of 



