CLASSES OF SCIENTIFIC TERMS. 79 



negative of the other. Negative terms may be either 

 abstract or concrete, adjectives or substantives. ' Priva- 

 tive ' terms indicate that a thing has been deprived of a 

 quality or attribute which it previously possessed, or might 

 have been capable of possessing. The idea of every attri- 

 bute, quality, or property of 6 an object' is as much real 

 as the object possessing it, or as the idea of the object itself. 

 Many of the attributes, &c., of objeots are not directly 

 perceptible by our consciousness, but a knowledge of their 

 existence is arrived at by reasoning processes. 



Similar terms are those which agree in the whole or in 

 part, and those which wholly agree are ' equivalent ' or 

 c synonymous.' Contradictory terms are those which, as 

 we have seen, are mutually exclusive, and do not admit of 

 degree. Every idea may have a contradictory one. Op- 

 posite terms are often confounded with contradictory ones, 

 but they are most properly applicable to cases of degree, 

 or quantitative ideas only ; ' cold ' and ' hot ' are opposite 

 terms, but ' cold ' and ' not-cold ' are contradictory ones. 

 ' Greater ' is not the contradictory, but the opposite, of 

 6 less,' because there may be the intermediate degree of 

 ' equal.' Extremes of degree are opposites, not negatives 

 or contradictories. All quantitative terms have inter- 

 mediate and medium degrees. 



By an ' absolute ' term is meant one which ' is loosed 

 from connection with anything else,' and which can be 

 thought of alone. It is, however, doubtful whether any 

 really absolute term can exist, because every idea has some 

 relation to some other idea, though sometimes apparently 

 only in a feeble degree. Every single existing thing must 

 form a part of the whole of existiog things, and occupy 

 in our ideas a part of the system of knowledge. We can 

 only form an accurate idea of an object, or class of objects, 

 by separating them in our minds from all other objects 



