IMPORTANCE OF ANALOGY. 285 



as a medium of proof, and as a source of new in- 

 formation. " I acknowledge, at the same time," he 

 continues, " that between the positive and the nega- 

 tive applications of this species of evidence, there is 

 an essential difference. When employed to refute an 

 objection, it may often furnish an argument irresist- 

 ably and unanswerably convincing ; when employed 

 as a medium of proof, it can never authorise more 

 than a probable conjecture, inviting and encourag- 

 ing further examination." But, as if sensible that, 

 this latter assertion took from analogy its due weight, 

 he proceeds to qualify it by adding, that " in some 

 instances, however, the probability resulting from a 

 concurrence of different analogies may rise so high 

 as to produce an effect on the belief scarcely dis- 

 tinguishable from moral certainty." 



(196.) Analogy, as it has been justly remarked, 

 as a ground of illustration, is not essentially distinct 

 from analogy as a ground of reasoning. For some 

 may be disposed fully to concede the illustrative use 

 of an appeal to the analogy of the moral and the 

 natural world, as a means of conciliating a favour- 

 able hearing to the philosophy of zoology, but dispute 

 the argumentative validity (and conclusiveness) of 

 such an appeal. It should be observed, then, that 

 unless that which purports to be an illustration of any 

 thing, has a real foundation in nature for the com- 

 parison instituted, it cannot throw any true light on 

 the subject to which it is applied. If the point of 

 comparison be assumed, the application of the pro- 

 posed illustration is only hypothetical ; and the 

 subject, in its proper nature, is rather obscured than 

 enlightened by the false representation of it. Such, 

 indeed, is the actual effect produced by fanciful 



