The Complete Aristotle (eng.)

‘But you have understanding of a stone:
therefore you understand of a stone.’ No: the one phrase is in the
genitive, ‘of a stone’, while the other is in the accusative, ‘a
stone’: and what was granted was that ‘you understand that, not of
that, of which you have understanding’, so that you understand not
‘of a stone’, but ‘the stone’.
    Thus that arguments of this kind do not prove solecism but
merely appear to do so, and both why they so appear and how you
should meet them, is clear from what has been said.
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33
    We must also observe that of all the arguments aforesaid it is
easier with some to see why and where the reasoning leads the
hearer astray, while with others it is more difficult, though often
they are the same arguments as the former. For we must call an
argument the same if it depends upon the same point; but the same
argument is apt to be thought by some to depend on diction, by
others on accident, and by others on something else, because each
of them, when worked with different terms, is not so clear as it
was. Accordingly, just as in fallacies that depend on ambiguity,
which are generally thought to be the silliest form of fallacy,
some are clear even to the man in the street (for humorous phrases
nearly all depend on diction; e.g. ‘The man got the cart down from
the stand’; and ‘Where are you bound?’ ‘To the yard arm’; and
‘Which cow will calve afore?’ ‘Neither, but both behind;’ and ‘Is
the North wind clear?’ ‘No, indeed; for it has murdered the beggar
and the merchant.” Is he a Good enough-King?’ ‘No, indeed; a
Rob-son’: and so with the great majority of the rest as well),
while others appear to elude the most expert (and it is a symptom
of this that they often fight about their terms, e.g. whether the
meaning of ‘Being’ and ‘One’ is the same in all their applications
or different; for some think that ‘Being’ and ‘One’ mean the same;
while others solve the argument of Zeno and Parmenides by asserting
that ‘One’ and ‘Being’ are used in a number of senses), likewise
also as regards fallacies of Accident and each of the other types,
some of the arguments will be easier to see while others are more
difficult; also to grasp to which class a fallacy belongs, and
whether it is a refutation or not a refutation, is not equally easy
in all cases.
    An incisive argument is one which produces the greatest
perplexity: for this is the one with the sharpest fang. Now
perplexity is twofold, one which occurs in reasoned arguments,
respecting which of the propositions asked one is to demolish, and
the other in contentious arguments, respecting the manner in which
one is to assent to what is propounded. Therefore it is in
syllogistic arguments that the more incisive ones produce the
keenest heart-searching. Now a syllogistic argument is most
incisive if from premisses that are as generally accepted as
possible it demolishes a conclusion that is accepted as generally
as possible. For the one argument, if the contradictory is changed
about, makes all the resulting syllogisms alike in character: for
always from premisses that are generally accepted it will prove a
conclusion, negative or positive as the case may be, that is just
as generally accepted; and therefore one is bound to feel
perplexed. An argument, then, of this kind is the most incisive,
viz. the one that puts its conclusion on all fours with the
propositions asked; and second comes the one that argues from
premisses, all of which are equally convincing: for this will
produce an equal perplexity as to what kind of premiss, of those
asked, one should demolish. Herein is a difficulty: for one must
demolish something, but what one must demolish is uncertain. Of
contentious arguments, on the other hand, the most incisive is the
one which, in the first place, is characterized by an initial
uncertainty whether it has been properly reasoned or not; and also
whether the solution depends on a false premiss or on the drawing
of a distinction; while, of the rest, the second place is held by
that whose solution clearly depends upon a distinction or a
demolition, and yet it does not reveal clearly which it is of the
premisses asked, whose demolition, or the drawing of a distinction
within it, will bring the solution about, but even leaves it vague
whether it is on the conclusion or on one of the premisses that the
deception depends.
    Now