82 GENERAL VIEW AND BASIS OF SCIENTIFIC RESEARCH. 



but to define that of the word ' copper,' we require only 

 to know the characteristic marks of that body. 



An ' abstract ' term is usually considered to be the 

 name of a property, quality, or attribute, considered apart, 

 or abstracted in thought from the object to which it 

 applies, or in which it resides, and from which it cannot 

 usually be separated. Thus weight, magnetism, ductility, 

 brittleness are abstract. When we define, we form an 

 abstract term. By a ' concrete ' term is meant the name 

 of a thing in which the abstract quality exists ; such, for 

 instance, as the terms platinum, iron, copper, glass, &c., 

 in which the properties of weight, magnetism, ductility, 

 and brittleness respectively reside. Many concrete terms 

 have corresponding abstract ones, but some have not ; and 

 the two kinds are often confounded. 1 All kinds of sub- 

 stances are capable of separate existence, but their attri- 

 butes, qualities, properties, and forces are incapable of 

 separate existence, and can only be separated in thought 

 by means of analysis and abstraction. 



CHAPTER VII. 



ON FACTS AND PROPOSITIONS IN SCIENCE. 



A FACT is a truth ; the simplest ideas are not truths ; for 

 instance, that of iron or of magnetism is not a truth. 

 A fact or truth requires a judgment or proposition by 

 which to express it, such as ' copper is red,' ' iron is mag- 

 netic,' &c. Contact with nature, through the medium oi 



1 A very valuable chapter on Scientific Terms and the Language 

 of Science ' may be found in Whewell's Philosophy of the Inductive 

 Sciences, vol. i. p. 48, also book viii. p. 449. 



