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called the same as a man, and what naturally travels upward the same
as fire: while a third use is found when it is rendered in reference
to some term drawn from Accident, as when the creature who is sitting,
or who is musical, is called the same as Socrates. For all these uses
mean to signify numerical unity. That what I have just said is true
may be best seen where one form of appellation is substituted for
another. For often when we give the order to call one of the people
who are sitting down, indicating him by name, we change our
description, whenever the person to whom we give the order happens not
to understand us; he will, we think, understand better from some
accidental feature; so we bid him call to us 'the man who is sitting'
or 'who is conversing over there'-clearly supposing ourselves to be
indicating the same object by its name and by its accident.
Part 8
Of 'sameness' then, as has been said,' three senses are to be
distinguished. Now one way to confirm that the elements mentioned
above are those out of which and through which and to which arguments
proceed, is by induction: for if any one were to survey propositions
and problems one by one, it would be seen that each was formed either
from the definition of something or from its property or from its
genus or from its accident. Another way to confirm it is through
reasoning. For every predicate of a subject must of necessity be
either convertible with its subject or not: and if it is convertible,
it would be its definition or property, for if it signifies the
essence, it is the definition; if not, it is a property: for this was
what a property is, viz. what is predicated convertibly, but does not
signify the essence. If, on the other hand, it is not predicated
convertibly of the thing, it either is or is not one of the terms
contained in the definition of the subject: and if it be one of those
terms, then it will be the genus or the differentia, inasmuch as the
definition consists of genus and differentiae; whereas, if it be not
one of those terms, clearly it would be an accident, for accident was
said' to be what belongs as an attribute to a subject without being
either its definition or its genus or a property.
Part 9
Next, then, we must distinguish between the classes of predicates in
which the four orders in question are found. These are ten in number:
Essence, Quantity, Quality, Relation, Place, Time, Position, State,
Activity, Passivity. For the accident and genus and property and
definition of anything will always be in one of these categories: for
all the propositions found through these signify either something's
essence or its quality or quantity or some one of the other types of
predicate. It is clear, too, on the face of it that the man who
signifies something's essence signifies sometimes a substance,
sometimes a quality, sometimes some one of the other types of
predicate. For when man is set before him and he says that what is set
there is 'a man' or 'an animal', he states its essence and signifies a
substance; but when a white colour is set before him and he says that
what is set there is 'white' or is 'a colour', he states its essence
and signifies a quality. Likewise, also, if a magnitude of a cubit be
set before him and he says that what is set there is a magnitude of a
cubit, he will be describing its essence and signifying a quantity.
Likewise, also, in the other cases: for each of these kinds of
predicate, if either it be asserted of itself, or its genus be
asserted of it, signifies an essence: if, on the other hand, one kind
of predicate is asserted of another kind, it does not signify an
essence, but a quantity or a quality or one of the other kinds of
predicate. Such, then, and so many, are the subjects on which
arguments take place, and the materials with which they start. How we
are to acquire them, and by what means we are to become well supplied
with them, falls next to be told.
Part 10
First, then, a definition must be given of a 'dialectical proposition'
and a 'dialectical problem'. For it is not every proposition nor yet