The Complete Aristotle (eng.)

demonstrating that it is
incommensurate. Accordingly, to exhaust all possible refutations we
shall have to have scientific knowledge of everything: for some
refutations depend upon the principles that rule in geometry and
the conclusions that follow from these, others upon those that rule
in medicine, and others upon those of the other sciences. For the
matter of that, the false refutations likewise belong to the number
of the infinite: for according to every art there is false proof,
e.g. according to geometry there is false geometrical proof, and
according to medicine there is false medical proof. By ‘according
to the art’, I mean ‘according to the principles of it’. Clearly,
then, it is not of all refutations, but only of those that depend
upon dialectic that we need to grasp the common-place rules: for
these stand in a common relation to every art and faculty. And as
regards the refutation that is according to one or other of the
particular sciences it is the task of that particular scientist to
examine whether it is merely apparent without being real, and, if
it be real, what is the reason for it: whereas it is the business
of dialecticians so to examine the refutation that proceeds from
the common first principles that fall under no particular special
study. For if we grasp the startingpoints of the accepted proofs on
any subject whatever we grasp those of the refutations current on
that subject. For a refutation is the proof of the contradictory of
a given thesis, so that either one or two proofs of the
contradictory constitute a refutation. We grasp, then, the number
of considerations on which all such depend: if, however, we grasp
this, we also grasp their solutions as well; for the objections to
these are the solutions of them. We also grasp the number of
considerations on which those refutations depend, that are merely
apparent-apparent, I mean, not to everybody, but to people of a
certain stamp; for it is an indefinite task if one is to inquire
how many are the considerations that make them apparent to the man
in the street. Accordingly it is clear that the dialectician’s
business is to be able to grasp on how many considerations depends
the formation, through the common first principles, of a refutation
that is either real or apparent, i.e. either dialectical or
apparently dialectical, or suitable for an examination.
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10
    It is no true distinction between arguments which some people
draw when they say that some arguments are directed against the
expression, and others against the thought expressed: for it is
absurd to suppose that some arguments are directed against the
expression and others against the thought, and that they are not
the same. For what is failure to direct an argument against the
thought except what occurs whenever a man does not in using the
expression think it to be used in his question in the same sense in
which the person questioned granted it? And this is the same thing
as to direct the argument against the expression. On the other
hand, it is directed against the thought whenever a man uses the
expression in the same sense which the answerer had in mind when he
granted it. If now any (i.e. both the questioner and the person
questioned), in dealing with an expression with more than one
meaning, were to suppose it to have one meaning-as e.g. it may be
that ‘Being’ and ‘One’ have many meanings, and yet both the
answerer answers and the questioner puts his question supposing it
to be one, and the argument is to the effect that ‘All things are
one’-will this discussion be directed any more against the
expression than against the thought of the person questioned? If,
on the other hand, one of them supposes the expression to have many
meanings, it is clear that such a discussion will not be directed
against the thought. Such being the meanings of the phrases in
question, they clearly cannot describe two separate classes of
argument. For, in the first place, it is possible for any such
argument as bears more than one meaning to be directed against the
expression and against the thought, and next it is possible for any
argument whatsoever; for the fact of being directed against the
thought consists not in the nature of the argument, but in the
special attitude of the answerer towards the points he concedes.
Next, all of them may be directed to the expression. For ‘to be
directed against the expression’ means in this