On Sophistical Refutations   

was the function of the art of examination. Now the art of examining

is a branch of dialectic: and this may prove a false conclusion

because of the ignorance of the answerer. Sophistic refutations on the

other hand, even though they prove the contradictory of his thesis, do

not make clear whether he is ignorant: for sophists entangle the

scientist as well with these arguments.

That we know them by the same line of inquiry is clear: for the same

considerations which make it appear to an audience that the points

required for the proof were asked in the questions and that the

conclusion was proved, would make the answerer think so as well, so

that false proof will occur through all or some of these means: for

what a man has not been asked but thinks he has granted, he would also

grant if he were asked. Of course, in some cases the moment we add the

missing question, we also show up its falsity, e.g. in fallacies

that depend on language and on solecism. If then, fallacious proofs of

the contradictory of a thesis depend on their appearing to refute,

it is clear that the considerations on which both proofs of false

conclusions and an apparent refutation depend must be the same in

number. Now an apparent refutation depends upon the elements

involved in a genuine one: for the failure of one or other of these

must make the refutation merely apparent, e.g. that which depends on

the failure of the conclusion to follow from the argument (the

argument ad impossible) and that which treats two questions as one and

so depends upon a flaw in the premiss, and that which depends on the

substitution of an accident for an essential attribute, and-a branch

of the last-that which depends upon the consequent: more over, the

conclusion may follow not in fact but only verbally: then, instead

of proving the contradictory universally and in the same respect and

relation and manner, the fallacy may be dependent on some limit of

extent or on one or other of these qualifications: moreover, there

is the assumption of the original point to be proved, in violation

of the clause 'without reckoning in the original point'. Thus we