98 NAMES AND PROPOSITIONS. 



a full Statement of the connotation it is all that a definition can be 

 required to be. 



§ 6. Of the two incomplete or unscientific modes of definition, and 

 in what they differ from the complete or scientific mode, enough has 

 now been said. We shall next examine an ancient doctrine, once 

 generally prevalent and still by no means exploded, which I regard as 

 the source of a great part of the obscurity hanging over some of the 

 most important processes of the understanding in the pursuit ofjxutlu- 

 According to this, the definitions of which we have now treated are 

 only one of two sorts into which definitions may be divided, viz., 

 definitions of names, and definitions of things. The fonner are intended 

 to explain the meaning of a term ; the latter, the nature of a thing ; the 

 last being incomparably the most important. 



This opinion was held by the ancient philosophers, and by their fol- 

 lowers, with the exception of the Nominalists ; but as the spirit of 

 modern metaphysics, until a recent period, has been on the whole a 

 Nominalist spirit, the notion of definitions of things has been to a cer- 

 tain extent in abeyance, still continuing, however, to breed confusion 

 in logic, by its consequences indeed rather than by itself Yet the 

 docti'ine in its own proper form now and then breaks out, and has ap- 

 peared (among other places) where it was scarcely to be expected, in 

 a deservedly popular work, Archbishop Whately's Logic. In a re- 

 view of that work published by me in the Westminster Review for 

 January 1828, and containing some opinions wliich I no longer enter- 

 tain, I find the following observations on the question now before us ; 

 obsex'vations with which my present views on that question are still 

 sufficiently in accordance. 



" The distinction between nominal and real definitions, between 

 definitions of words and what are called definitions of things, though 

 conformable to the ideas of most of the Aristotelian logicians, cannot, 

 as it appears to us, be maintained. We apprehend that no definition 

 is ever intended to ' explain and unfold the nature of the thing.' It is 

 some confirmation of our opinion, that none of those writers who have 

 thought that there were definitions of things', have ever succeeded in 

 discovering any criterion by which the definition of a thing can be dis- 

 tinguished from any other proposition relating to the thing. The 

 definition, they say, unfolds the nature of the thing : but no definition 

 can unfold its whole nature ; and every proposition in which any qual- 

 ity whatever is predicated of the thing, unfolds some part of its nature. 

 The true state of the case we take to be this. All definitions are of 

 names, and of names only : but, in some definitions, it is clearly ap- 

 parent, that nothing is intended except to explain the meaning of the 

 word ; while in others, besides explaining the meaning of the word, it 

 is intended to be implied that there exists a thing, corresponding to 

 the word. Whether this be or be not implied in any given case, 

 cannot be collected from the mere form of the expression. ' A cen- 

 taur is an animal with the upper parts of a man and the lower parts of 

 a horse,' and ' A triangle is a rectilineal figure with three sides,' are, 

 in form, expressions precisely similar ; although in the former it is not 

 implied that any thing, conformable to the term, really exists, while in 

 the latter it is ; as may be seen by substituting, in both definitions, the 

 Vford means fori*. In the first expression, ' A centaur means an an- 



