374 FALLACIES. 



fore, assume the proposition which they are brought to prove : 

 their use is, to aid the apprehension of it ; to make clearly and 

 vividly comprehended what it is that the person who employs 

 the metaphor is proposing to make out ; and sometimes also, 

 by what media he proposes to do so. For an apt metaphor, 

 though it cannot prove, often suggests the proof. 



For instance, when D Alembert (I believe) remarked that 

 in certain governments, only two creatures find their way to the 

 highest places, the eagle and the serpent ; the metaphor not 

 only conveys with great vividness the assertion intended, but 

 contributes towards substantiating it, by suggesting, in a lively 

 manner, the means by which the two opposite characters thus 

 typified effect their rise. When it is said that a certain person 

 misunderstands another because the lesser of two objects 

 -cannot comprehend the greater, the application of what is true 

 in the literal sense of the word comprehend, to its metaphorical 

 sense, points to the fact which is the ground and justification 

 of the assertion, viz. that one mind cannot thoroughly under 

 stand another unless it can contain it in itself, that is, unless 

 it possesses all that is contained in the other. When it is 

 urged as an argument for education, that if the soil is left 

 uncultivated, weeds will spring up, the metaphor, though 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. For, the reason why weeds grow 

 in an uncultivated soil, is that the seeds of worthless products 

 exist everywhere, and can germinate and grow in almost all 

 circumstances, while the reverse is the case with those which 

 are valuable ; and this being equally true of mental products, 

 this mode of conveying an argument, independently of its 

 rhetorical advantages, has a logical value ; since it not only 

 suggests the grounds of the conclusion, but points to another 

 case in which those grounds have been found, or at least 

 deemed to be, sufficient 



On the other hand, when Bacon, who is equally conspi 

 cuous 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 carries 



