x INTRODUCTION 



would discover a way of explaining it in terms of the 

 easily comprehensible nature of a table. 



Table No. 2 is my scientific table. It is a more recent 

 acquaintance and I do not feel so familiar with it. It 

 does not belong to the world previously mentioned — 

 that world which spontaneously appears around me when 

 I open my eyes, though how much of it is objective and 

 how much subjective I do not here consider. It is part 

 of a world which in more devious ways has forced 

 itself on my attention. My scientific table is mostly 

 emptiness. Sparsely scattered in that emptiness are ! 

 numerous electric charges rushing about with great 

 speed; but their combined bulk amounts to less than a 

 billionth of the bulk of the table itself. Notwithstanding 

 its strange construction it turns out to be an entirely 

 efficient table. It supports my writing paper as satisfac- 

 torily as table No. 1 ; for when I lay the paper on it the 

 little electric particles with their headlong speed keep 

 on hitting the underside, so that the paper is maintained 

 in shuttlecock fashion at a nearly steady level. If I lean 

 upon this table I shall not go through; or, to be strictly 

 accurate, the chance of my scientific elbow going through 

 my scientific table is so excessively small that it can be 

 neglected in practical life. Reviewing their properties 

 one by one, there seems to be nothing to choose between 

 the two tables for ordinary purposes; but when ab- 

 normal circumstances befall, then my scientific table 

 shows to advantage. If the house catches fire my sci- 

 entific table will dissolve quite naturally into scientific 

 smoke, whereas my familiar table undergoes a metamor- 

 phosis of its substantial nature which I can only regard 

 as miraculous. 



There is nothing substantial about my second table. 

 It is nearly all empty space — space pervaded, it is true, 



