IMPORTANCE OF ANALOGY. 985 
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 
