496 FALLACIES. 



weak than to a strong constitution. If this be owing to a cause which 

 equally operates in what relates to the mind, the same conclusion will 

 hold there likewise. J3ut such is really the fact. For the body's 

 liability to these sudden and uncontrollable motions arises from irrita- 

 bility, that is, unusual susceptibility of being moved out of its ordinary 

 course by transient influences : which may equally be said of the mind. 

 And this susceptibility, whether of mind or body, must arise from a 

 weakness of the forces which maintain and carry on the ordinary ac- 

 tion of the system. All this is conveyed in Mr. Carlyle's short sen- 

 tence. And since the causes are alike in the body and in the mind, the 

 analogy is a just one, and the maxim holds of the one as much as of 

 the other. 



Thus we see that the metaphor, although no proof but a statement 

 of the thing to be proved, states it in terms which, by suggesting a 

 parallel case, put the mind upon the track of the real proof The 

 hearer says, " Strength does not manifest itself in spasms — very true ; 

 and for what reason V Then in discovering the reason, he finds it pre- 

 cisely as applicable to the mind as it is to the body. This mode, there- 

 fore, of conveying an argument, independently of its rhetorical advan- 

 tages, has a logical value; since it not only suggests the grounds of 

 the conclusion, but points out another case in which those gi'ounds 

 have been found, or at least deemed to be, sufficient. 



On the other hand, when Bacon, who is equally conspicuous in the 

 use and abuse of figurative illustration, says that the stream of time 

 has brought down to us only the least valuable part of the writings of 

 the ancients, as a river can-ies fi"oth and straws floating on its surface, 

 while more weighty objects sink to the bottom; this, even if the asser- 

 tion illustrated by it were true, would be no good illustration, there 

 being no parity of cause. The levity by which substances float on a 

 stream, and the levity which is synonymous with worthlessness, have 

 nothing in common except the name ; and (to show how little value 

 there is in the metaphor) we need only change the word into htioyancy, 

 to turn the semblance of argument involved in Bacon's illustration 

 directly against himself 



A metaphor, then, is not to be considered as an argument, but as 

 an assertion that an argument exists ; that a parity subsists between 

 the case from which the metaphor is drawn and that to which it is 

 applied. This parity may exist though the two cases be apparently 

 very remote from one another: the only resemblance existing between 

 them may be a resemblance of relations, an analog}^ in Ferguson's and 

 Archbishop Whately's sense. As in the instance quoted from Mr. 

 Carlyle : there is no resemblance between convulsions of the body and 

 fits of passion in the mind, considered in themselves ; the resemblance 

 is between the relation which convulsions of the body bear to its ordi- 

 nary motions, and that which fits of passion in the mind bear to its 

 steadier feelings. Thus, where the real difference between the two 

 cases is the widest ; where the metaphor seems the most far-fetched, 

 the analogy the most remote ; dnd where, consequently, a limited and 

 literal understanding would be most apt to shut itself up \vithin its 

 intrenchment of prose, and refuse admittance to the metaphor, under 

 an idea that cases so very unlike can throw no light upon each other ; 

 it is often in those very cases that the argument which the metaphor 

 involves and suggests is the most conclusive. 



