The Complete Aristotle (eng.)

rendered the property relatively to what does not
exist:-for while air may exist, even though there exist no animal
so constituted as to breathe the air, it is not possible to breathe
it if no animal exist: so that it will not, either, be a property
of air to be such as can be breathed at a time when there exists no
animal such as to breathe it and so it follows that ‘breathable’
could not be a property of air.
    For constructive purposes, see if in rendering the property
potentially he renders the property either relatively to something
that exists, or to something that does not exist, when the
potentiality in question can belong to what does not exist: for
then what has been stated not to be a property will be a property.
Thus e.g.) he who renders it as a property of ‘being’ to be
‘capable of being acted upon or of acting’, in rendering the
property potentially, has rendered the property relatively to
something that exists: for when ‘being’ exists, it will also be
capable of being acted upon or of acting in a certain way: so that
to be ‘capable of being acted upon or of acting’ would be a
property of ‘being’.
    Next, for destructive purposes, see if he has stated the
property in the superlative: for then what has been stated to be a
property will not be a property. For people who render the property
in that way find that of the object of which the description is
true, the name is not true as well: for though the object perish
the description will continue in being none the less; for it
belongs most nearly to something that is in being. An example would
be supposing any one were to render ‘the lightest body’ as a
property of ‘fire’: for, though fire perish, there eh re will still
be some form of body that is the lightest, so that ‘the lightest
body’ could not be a property of fire. For constructive purposes,
on the other hand, see if he has avoided rendering the property in
the superlative: for then the property will in this respect have
been property of man has not rendered the property correctly
stated. Thus (e.g.) inasmuch as he in the superlative, the property
would in who states ‘a naturally civilized animal’ as a this
respect have been correctly stated.

Topics, Book VI
    Translated by W. A. Pickard-Cambridge
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    div id="book6" class="book" title="Book VI">
    1
    The discussion of Definitions falls into five parts. For you
have to show either (1) that it is not true at all to apply the
expression as well to that to which the term is applied (for the
definition of Man ought to be true of every man); or (2) that
though the object has a genus, he has failed to put the object
defined into the genus, or to put it into the appropriate genus
(for the framer of a definition should first place the object in
its genus, and then append its differences: for of all the elements
of the definition the genus is usually supposed to be the principal
mark of the essence of what is defined): or (3) that the expression
is not peculiar to the object (for, as we said above as well, a
definition ought to be peculiar): or else (4) see if, though he has
observed all the aforesaid cautions, he has yet failed to define
the object, that is, to express its essence. (5) It remains, apart
from the foregoing, to see if he has defined it, but defined it
incorrectly.
    Whether, then, the expression be not also true of that of which
the term is true you should proceed to examine according to the
commonplace rules that relate to Accident. For there too the
question is always ‘Is so and so true or untrue?’: for whenever we
argue that an accident belongs, we declare it to be true, while
whenever we argue that it does not belong, we declare it to be
untrue. If, again, he has failed to place the object in the
appropriate genus, or if the expression be not peculiar to the
object, we must go on to examine the case according to the
commonplace rules that relate to genus and property.
    It remains, then, to prescribe how to investigate whether the
object has been either not defined at all, or else defined
incorrectly. First, then, we must proceed to examine if it has been
defined incorrectly: for with anything it is easier to do it than
to do it correctly. Clearly, then, more mistakes are made in the
latter task on account of its greater difficulty. Accordingly the
attack becomes easier in the latter case than in the former.
    Incorrectness falls into two branches: (1) first, the use of
obscure language (for the