The Complete Aristotle (eng.)

same
principles. Accordingly, no art that is a method of showing the
nature of anything proceeds by asking questions: for it does not
permit a man to grant whichever he likes of the two alternatives in
the question: for they will not both of them yield a proof.
Dialectic, on the other hand, does proceed by questioning, whereas
if it were concerned to show things, it would have refrained from
putting questions, even if not about everything, at least about the
first principles and the special principles that apply to the
particular subject in hand. For suppose the answerer not to grant
these, it would then no longer have had any grounds from which to
argue any longer against the objection. Dialectic is at the same
time a mode of examination as well. For neither is the art of
examination an accomplishment of the same kind as geometry, but one
which a man may possess, even though he has not knowledge. For it
is possible even for one without knowledge to hold an examination
of one who is without knowledge, if also the latter grants him
points taken not from thing that he knows or from the special
principles of the subject under discussion but from all that range
of consequences attaching to the subject which a man may indeed
know without knowing the theory of the subject, but which if he do
not know, he is bound to be ignorant of the theory. So then clearly
the art of examining does not consist in knowledge of any definite
subject. For this reason, too, it deals with everything: for every
‘theory’ of anything employs also certain common principles. Hence
everybody, including even amateurs, makes use in a way of dialectic
and the practice of examining: for all undertake to some extent a
rough trial of those who profess to know things. What serves them
here is the general principles: for they know these of themselves
just as well as the scientist, even if in what they say they seem
to the latter to go wildly astray from them. All, then, are engaged
in refutation; for they take a hand as amateurs in the same task
with which dialectic is concerned professionally; and he is a
dialectician who examines by the help of a theory of reasoning. Now
there are many identical principles which are true of everything,
though they are not such as to constitute a particular nature, i.e.
a particular kind of being, but are like negative terms, while
other principles are not of this kind but are special to particular
subjects; accordingly it is possible from these general principles
to hold an examination on everything, and that there should be a
definite art of so doing, and, moreover, an art which is not of the
same kind as those which demonstrate. This is why the contentious
reasoner does not stand in the same condition in all respects as
the drawer of a false diagram: for the contentious reasoner will
not be given to misreasoning from any definite class of principles,
but will deal with every class.
    These, then, are the types of sophistical refutations: and that
it belongs to the dialectician to study these, and to be able to
effect them, is not difficult to see: for the investigation of
premisses comprises the whole of this study.
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12
    So much, then, for apparent refutations. As for showing that the
answerer is committing some fallacy, and drawing his argument into
paradox-for this was the second item of the sophist’s programme-in
the first place, then, this is best brought about by a certain
manner of questioning and through the question. For to put the
question without framing it with reference to any definite subject
is a good bait for these purposes: for people are more inclined to
make mistakes when they talk at large, and they talk at large when
they have no definite subject before them. Also the putting of
several questions, even though the position against which one is
arguing be quite definite, and the claim that he shall say only
what he thinks, create abundant opportunity for drawing him into
paradox or fallacy, and also, whether to any of these questions he
replies ‘Yes’ or replies ‘No’, of leading him on to statements
against which one is well off for a line of attack. Nowadays,
however, men are less able to play foul by these means than they
were formerly: for people rejoin with the question, ‘What has that
to do with the original subject?’ It is, too, an elementary rule
for eliciting some fallacy or paradox that one should never put a
controversial