158 NAMES AND PROPOSITIONS. 



treated are only one of two sorts into which definitions may 

 be divided, viz. definitions of names, and definitions of things. 

 The former 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 followers, 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 defini- 

 tions of things has been to a certain extent in abeyance, still 

 continuing, however, to breed confusion in logic, by its conse- 

 quences indeed rather than by itself. Yet the doctrine in its 

 own proper form now and then breaks out, and has appeared 

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

 a justly admired work, Archbishop Whately's Logic.* In a 

 review of that work published by me in the Westminster 



* In the fuller discussion which Archbishop Whately has given to this 

 subject in his later editions, he almost ceases to regard the definitions of names 

 and those of things as, in any important sense, distinct. He seems (9th ed. 

 p. 145) to limit the notion of a Real Definition to one which " explains any- 

 thing more of the nature of the thing than is implied in the name ;" (including 

 under the word "implied," not only what the name connotes, but everything 

 which can be deduced by reasoning from the attributes connoted). Even this, 

 as he adds, is usually called, not a Definition, but a Description ; and (as it 

 seems to me) rightly so called. A Description, I conceive, can only be ranked 

 among Definitions, when taken (as in the case of the zoological definition of 

 man) to fulfil the true office of a Definition, by declaring the connotation given 

 to a word in some special use, as a term of science or art : which special conno- 

 tation of course would not be expressed by the proper definition of the word in 

 its ordinary employment. 



Mr. De Morgan, exactly reversing the doctrine of Archbishop Whately, un- 

 derstands by a Real Definition one which contains less than the Nominal Defi- 

 nition, provided only that what it contains is sufficient for distinction. " By 

 real definition I mean such an explanation of the word, be it the whole of the 

 meaning or only part, as will be sufficient to separate the things contained 

 under that word from all others. Thus the following, I believe, is a complete 

 definition of an elephant : An animal which naturally drinks by drawing the 

 water into its nose, and then spurting it into its mouth." Formal Logic, p. 36. 

 Mr. De Morgan's general proposition and his example are at variance ; for the 

 peculiar mode of drinking of the elephant certainly forms no part of the mean- 

 ing of the word elephant. It could not be said, because a person happened to 

 be ignorant of this property, that he did not know what an elephant means. 



