The Complete Aristotle (eng.)

will result from them is more obvious in
advance.
    One should also, wherever possible, secure the universal premiss
by a definition relating not to the precise terms themselves but to
their co-ordinates; for people deceive themselves, whenever the
definition is taken in regard to a co-ordinate, into thinking that
they are not making the admission universally. An instance would
be, supposing one had to secure the admission that the angry man
desires vengeance on account of an apparent slight, and were to
secure this, that ‘anger’ is a desire for vengeance on account of
an apparent slight: for, clearly, if this were secured, we should
have universally what we intend. If, on the other hand, people
formulate propositions relating to the actual terms themselves,
they often find that the answerer refuses to grant them because on
the actual term itself he is readier with his objection, e.g. that
the ‘angry man’ does not desire vengeance, because we become angry
with our parents, but we do not desire vengeance on them. Very
likely the objection is not valid; for upon some people it is
vengeance enough to cause them pain and make them sorry; but still
it gives a certain plausibility and air of reasonableness to the
denial of the proposition. In the case, however, of the definition
of ‘anger’ it is not so easy to find an objection.
    Moreover, formulate your proposition as though you did so not
for its own sake, but in order to get at something else: for people
are shy of granting what an opponent’s case really requires.
Speaking generally, a questioner should leave it as far as possible
doubtful whether he wishes to secure an admission of his
proposition or of its opposite: for if it be uncertain what their
opponent’s argument requires, people are more ready to say what
they themselves think.
    Moreover, try to secure admissions by means of likeness: for
such admissions are plausible, and the universal involved is less
patent; e.g. make the other person admit that as knowledge and
ignorance of contraries is the same, so too perception of
contraries is the same; or vice versa, that since the perception is
the same, so is the knowledge also. This argument resembles
induction, but is not the same thing; for in induction it is the
universal whose admission is secured from the particulars, whereas
in arguments from likeness, what is secured is not the universal
under which all the like cases fall.
    It is a good rule also, occasionally to bring an objection
against oneself: for answerers are put off their guard against
those who appear to be arguing impartially. It is useful too, to
add that ‘So and so is generally held or commonly said’; for people
are shy of upsetting the received opinion unless they have some
positive objection to urge: and at the same time they are cautious
about upsetting such things because they themselves too find them
useful. Moreover, do not be insistent, even though you really
require the point: for insistence always arouses the more
opposition. Further, formulate your premiss as though it were a
mere illustration: for people admit the more readily a proposition
made to serve some other purpose, and not required on its own
account. Moreover, do not formulate the very proposition you need
to secure, but rather something from which that necessarily
follows: for people are more willing to admit the latter, because
it is not so clear from this what the result will be, and if the
one has been secured, the other has been secured also. Again, one
should put last the point which one most wishes to have conceded;
for people are specially inclined to deny the first questions put
to them, because most people in asking questions put first the
points which they are most eager to secure. On the other hand, in
dealing with some people propositions of this sort should be put
forward first: for ill-tempered men admit most readily what comes
first, unless the conclusion that will result actually stares them
in the face, while at the close of an argument they show their
ill-temper. Likewise also with those who consider themselves smart
at answering: for when they have admitted most of what you want
they finally talk clap-trap to the effect that the conclusion does
not follow from their admissions: yet they say ‘Yes’ readily,
confident in their own character, and imagining that they cannot
suffer any reverse. Moreover, it is well to expand the argument and
insert things that it does not require at all,