350 BC

                                     TOPICS

                                  by Aristotle

                     translated by W. A. Pickard-Cambridge

                              Book I

                                 1

  OUR treatise proposes to find a line of inquiry whereby we shall
be able to reason from opinions that are generally accepted about
every problem propounded to us, and also shall ourselves, when
standing up to an argument, avoid saying anything that will obstruct
us. First, then, we must say what reasoning is, and what its varieties
are, in order to grasp dialectical reasoning: for this is the object
of our search in the treatise before us.

  Now reasoning is an argument in which, certain things being laid
down, something other than these necessarily comes about through them.
(a) It is a 'demonstration', when the premisses from which the
reasoning starts are true and primary, or are such that our
knowledge of them has originally come through premisses which are
primary and true: (b) reasoning, on the other hand, is
'dialectical', if it reasons from opinions that are generally
accepted. Things are 'true' and 'primary' which are believed on the
strength not of anything else but of themselves: for in regard to
the first principles of science it is improper to ask any further
for the why and wherefore of them; each of the first principles should
command belief in and by itself. On the other hand, those opinions are
'generally accepted' which are accepted by every one or by the
majority or by the philosophers-i.e. by all, or by the majority, or by
the most notable and illustrious of them. Again (c), reasoning is
'contentious' if it starts from opinions that seem to be generally
accepted, but are not really such, or again if it merely seems to
reason from opinions that are or seem to be generally accepted. For
not every opinion that seems to be generally accepted actually is
generally accepted. For in none of the opinions which we call
generally accepted is the illusion entirely on the surface, as happens
in the case of the principles of contentious arguments; for the nature
of the fallacy in these is obvious immediately, and as a rule even
to persons with little power of comprehension. So then, of the
contentious reasonings mentioned, the former really deserves to be
called 'reasoning' as well, but the other should be called
'contentious reasoning', but not 'reasoning', since it appears to
reason, but does not really do so. Further (d), besides all the
reasonings we have mentioned there are the mis-reasonings that start
from the premisses peculiar to the special sciences, as happens (for
example) in the case of geometry and her sister sciences. For this
form of reasoning appears to differ from the reasonings mentioned
above; the man who draws a false figure reasons from things that are
neither true and primary, nor yet generally accepted. For he does
not fall within the definition; he does not assume opinions that are
received either by every one or by the majority or by
philosophers-that is to say, by all, or by most, or by the most
illustrious of them-but he conducts his reasoning upon assumptions
which, though appropriate to the science in question, are not true;
for he effects his mis-reasoning either by describing the
semicircles wrongly or by drawing certain lines in a way in which they
could not be drawn.

  The foregoing must stand for an outline survey of the species of
reasoning. In general, in regard both to all that we have already
discussed and to those which we shall discuss later, we may remark
that that amount of distinction between them may serve, because it
is not our purpose to give the exact definition of any of them; we
merely want to describe them in outline; we consider it quite enough
from the point of view of the line of inquiry before us to be able
to recognize each of them in some sort of way.

                                 2

  Next in order after the foregoing, we must say for how many and
for what purposes the treatise is useful. They are
three-intellectual training, casual encounters, and the
philosophical sciences. That it is useful as a training is obvious
on the face of it. The possession of a plan of inquiry will enable
us more easily to argue about the subject proposed. For purposes of
casual encounters, it is useful because when we have counted up the
opinions held by most people, we shall meet them on the ground not
of other people's convictions but of their own, while we shift the
ground of any argument that they appear to us to state unsoundly.
For the study of the philosophical sciences it is useful, because
the ability to raise searching difficulties on both sides of a subject
will make us detect more easily the truth and error about the
several points that arise. It has a further use in relation to the
ultimate bases of the principles used in the several sciences. For
it is impossible to discuss them at all from the principles proper
to the particular science in hand, seeing that the principles are
the prius of everything else: it is through the opinions generally
held on the particular points that these have to be discussed, and
this task belongs properly, or most appropriately, to dialectic: for
dialectic is a process of criticism wherein lies the path to the
principles of all inquiries.

                                 3

  We shall be in perfect possession of the way to proceed when we