INTRODUCTION xi 



by fields of force, but these are assigned to the category 

 of "influences", not of "things". Even in the minute 

 part which is not empty we must not transfer the old 

 notion of substance. In dissecting matter into electric 

 charges we have travelled far from that picture of it 

 which first gave rise to the conception of substance, and 

 the meaning of that conception — if it ever had any — 

 has been lost by the way. The whole trend of modern 

 scientific views is to break down the separate categories 

 of "things", "influences", "forms", etc., and to substi- 

 tute a common background of all experience. Whether 

 we are studying a material object, a magnetic field, a 

 geometrical figure, or a duration of time, our scientific 

 information is summed up in measures ; neither the appa- 

 ratus of measurement nor the mode of using it suggests 

 that there is anything essentially different in these prob- 

 lems. The measures themselves afford no ground for 

 a classification by categories. We feel it necessary to 

 concede some background to the measures — an external 

 world; but the attributes of this world, except in so far 

 as they 'are reflected in the measures, are outside scien- 

 tific scrutiny. Science has at last revolted against 

 attaching the exact knowledge contained in these meas- 

 urements to a traditional picture-gallery of conceptions 

 which convey no authentic information of the back- 

 ground and obtrude irrelevancies into the scheme of 

 knowledge. 



I will not here stress .further the non-substantiality 

 of electrons, since it is scarcely necessary to the present 

 line of thought. Conceive them as substantially as you 

 will, there is a vast difference between my scientific table 

 with its substance (if any) thinly scattered in specks 

 in a region mosdy empty and the table of everyday 

 conception which we regard as the type of solid reality 



