From the nature of error, whose concept, as we noted, contains besides falsity the semblance of truth as an essential characteristic, the following important rule results for our cognition:
In order to avoid error -- and absolutely unavoidable is no error although it may be relatively so in cases where, even at the risk of erring, it is unavoidable for us to judge -- in order, then, to avoid error, one must try to discover and explain its source, semblance. This has been done by very few philosophers. They have sought to refute the errors themselves without indicating the semblance from which they have sprung. This disclosure and solution of semblance, however, is a far greater service to truth than the direct refutation of the errors themselves, by which one cannot block their source and prevent the same semblance, because one does not know it, from leading again to errors in other cases....
By explaining semblance one moreover accords a kind of equity to the erring person. For no one will admit that he has erred without some semblance of truth which might have deceived perhaps even a more perspicacious person; for here the subjective reasons count.
Immanuel Kant,
Logic, Hartman & Schwarz, trs. Dover (New York: 1974) 59-60. The rule has a good Aristotelian provenance, and is salutary advice on all occasions.
