MOTION, FORCE, MATTER 339 



to determine the character of these more concrete types of 

 entity. The scientific problem of matter is the problem of the 

 ultimate stuff of nature, not in the sense of the most abstract 

 natural entity, but in the sense of that type of event to 

 which all other events can be related as attributes, relations, 

 processes, happenings, or changes. Material events are funda- 

 mental only in the sense that all other events are referential 

 toward them. 



The scientific problem of matter, therefore, reduces to the 

 first of those given above. Matter is that which is most 

 adequately described by such vague common sense words 

 as "thing," "body," "object," and "substance." The 

 further problem, then, is to determine as precisely as possible 

 what these terms reduce to at the empirical level, what 

 content the scientist gives to them when he employs them as 

 tools in his investigation, and by what operational tech- 

 niques the latter may be derived from the former. 



When one turns to the problem of the empirical founda- 

 tion of the concept of matter he is impressed with an im- 

 portant feature. Things are complexes of properties and 

 aspects. A table, for example, is a complex of shape, color, 

 weight, hardness, gloss, smoothness, warmth, etc. Further- 

 more, it appears at the empirical level that by the substance 

 or material of a thing one can mean only this complex or 

 some selected part of it. There is nothing given in observa- 

 tion that can be called the substratum of the qualities. One 

 can observe only the qualities, not "that which possesses the 

 qualities." At this level matter must be defined not as that 

 which explains the given, but as the given itself. Locke's 

 conception of substance as the unknowable substratum, 

 Berkeley's conception of substance as God, Mill's conception 

 as the Permanent Possibility of Sensation, and all historic 

 atomisms, are not descriptions of the given but interpreta- 

 tions of it through constructs and hypotheses. On the 

 strictly empirical level a thing must be defined simply as a 

 certain togetherness of sense-data; the object is the totality 

 of its manifestations or attributes. 



