340 INTRODUCTION TO PHILOSOPHY OF SCIENCE 



However, although matter is capable of definition only 

 as a complex of qualities and relations, certain of the latter 

 are considered more basic than others, and hence as affording 

 the defining properties of matter. The empirical properties 

 of matter are approximately as follows : 



1. Location and continuous endurance through time. A 

 complex of properties which is called " matter v seems to 

 have at least an approximate location in time, i.e., one is 

 able to say that there are certain complexes which it precedes 

 and certain others which it follows. This involves no more 

 precision than is possible upon the empirical level. Further- 

 more, the complex seems to endure, usually through a longer 

 rather than a shorter time; hence there is no such entity as an 

 instantaneous thing, and a complex of properties is more 

 certainly characterizable as matter if it lasts for a relatively 

 long time. Finally, matter seems to have a temporal identity; 

 it endures continuously and exhibits no breaks in its life. 



2. Relative permanence. A complex which is called "mat- 

 ter" is usually relatively unchanging. When the change is 

 rapid the complex is commonly spoken of as a happening 

 rather than as a thing; a flash of lightning, the fall of a leaf, 

 an explosion, and a fire are not matter but happenings. Here, 

 again, there is nothing empirical corresponding to "that 

 which changes" except as one means by this phrase simply 

 the complex itself. " Consider, say, a wall-paper which fades 

 in the course of years. It is an effort not to conceive of it as 

 one ' thing ' whose color is slightly different at one time from 

 what it is at another. But what do we really know about it? 

 We know that under suitable circumstances — i.e., when we 

 are, as is said, 'in the room' — we perceive certain colors in a 

 certain pattern: not always precisely the same colors, but 

 sufficiently similar to feel familiar. If we can state the laws 

 according to which the color varies, we can state all that is 

 empirically verifiable; the assumption that there is a con- 

 stant entity, the wall-paper, which 'has' these various colors 

 at various times, is a piece of gratuitous metaphysics. We 

 may, if we like, define the wall-paper as the series of its 



