INTRODUCTION 



I have settled down to the task of writing these lectures 

 and have drawn up my chairs to my two tables. Two 

 tables! Yes; there are duplicates of every object about 

 me — two tables, two chairs, two pens. 



This is not a very profound beginning to a course 

 which ought to reach transcendent levels of scientific 

 philosophy. But we cannot touch bedrock immediately; 

 we must scratch a bit at the surface of things first. And 

 whenever I begin to scratch the first thing I strike is — 

 my two tables. 



One of them has been familiar to me from earliest 

 years. It is a commonplace object of that environment 

 which I call the world. How shall I describe it? It has 

 extension; it is comparatively permanent; it is coloured; 

 above all it is substantial. By substantial I do not merely 

 mean that it does not collapse when I lean upon it ; I mean 

 that it is constituted of "substance" and by that word 

 I am trying to convey to you some conception of its 

 intrinsic nature. It is a thing; not like space, which is 

 a mere negation; nor like time, which is — Heaven 

 knows what ! But that will not help you to my meaning 

 because it is the distinctive characteristic of a "thing" 

 to have this substantiality, and I do not think substan- 

 tiality can be described better than by saying that it is 

 the kind of nature exemplified by an ordinary table. And 

 so we go round in circles.^ After all if you are a plain 

 commonsense man, not too much worried with scien- 

 tific scruples, you will be confident that you understand 

 the nature of an ordinary table. I have even heard 

 of plain men who had the idea that they could better 

 understand the mystery of their own nature if scientists 



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