coloured or that walking is in motion. For a predicate drawn from
the genus is never ascribed to the species in an inflected form, but
always the genera are predicated of their species literally; for the
species take on both the name and the definition of their genera. A
man therefore who says that white is 'coloured' has not rendered
'coloured' as its genus, seeing that he has used an inflected form,
nor yet as its property or as its definition: for the definition and
property of a thing belong to it and to nothing else, whereas many
things besides white are coloured, e.g. a log, a stone, a man, and a
horse. Clearly then he renders it as an accident.

  Another rule is to examine all cases where a predicate has been
either asserted or denied universally to belong to something. Look
at them species by species, and not in their infinite multitude: for
then the inquiry will proceed more directly and in fewer steps. You
should look and begin with the most primary groups, and then proceed
in order down to those that are not further divisible: e.g. if a man
has said that the knowledge of opposites is the same, you should
look and see whether it be so of relative opposites and of
contraries and of terms signifying the privation or presence of
certain states, and of contradictory terms. Then, if no clear result
be reached so far in these cases, you should again divide these
until you come to those that are not further divisible, and see (e.g.)
whether it be so of just deeds and unjust, or of the double and the
half, or of blindness and sight, or of being and not-being: for if
in any case it be shown that the knowledge of them is not the same
we shall have demolished the problem. Likewise, also, if the predicate
belongs in no case. This rule is convertible for both destructive
and constructive purposes: for if, when we have suggested a
division, the predicate appears to hold in all or in a large number of
cases, we may then claim that the other should actually assert it
universally, or else bring a negative instance to show in what case it
is not so: for if he does neither of these things, a refusal to assert
it will make him look absurd.

  Another rule is to make definitions both of an accident and of its
subject, either of both separately or else of one of them, and then
look and see if anything untrue has been assumed as true in the
definitions. Thus (e.g.) to see if it is possible to wrong a god,
ask what is 'to wrong'? For if it be 'to injure deliberately', clearly
it is not possible for a god to be wronged: for it is impossible
that God should be injured. Again, to see if the good man is
jealous, ask who is the 'jealous' man and what is 'jealousy'. For if
'jealousy' is pain at the apparent success of some well-behaved
person, clearly the good man is not jealous: for then he would be bad.
Again, to see if the indignant man is jealous, ask who each of them
is: for then it will be obvious whether the statement is true or
false; e.g. if he is 'jealous' who grieves at the successes of the
good, and he is 'indignant' who grieves at the successes of the
evil, then clearly the indignant man would not be jealous. A man
should substitute definitions also for the terms contained in his
definitions, and not stop until he comes to a familiar term: for often
if the definition be rendered whole, the point at issue is not cleared
up, whereas if for one of the terms used in the definition a
definition be stated, it becomes obvious.

  Moreover, a man should make the problem into a proposition for
himself, and then bring a negative instance against it: for the
negative instance will be a ground of attack upon the assertion.
This rule is very nearly the same as the rule to look into cases where
a predicate has been attributed or denied universally: but it
differs in the turn of the argument.

  Moreover, you should define what kind of things should be called
as most men call them, and what should not. For this is useful both
for establishing and for overthrowing a view: e.g. you should say that
we ought to use our terms to mean the same things as most people
mean by them, but when we ask what kind of things are or are not of
such and such a kind, we should not here go with the multitude: e.g.
it is right to call 'healthy' whatever tends to produce health, as
do most men: but in saying whether the object before us tends to
produce health or not, we should adopt the language no longer of the
multitude but of the doctor.

                                 3

  Moreover, if a term be used in several senses, and it has been
laid down that it is or that it is not an attribute of S, you should
show your case of one of its several senses, if you cannot show it
of both. This rule is to be observed in cases where the difference
of meaning is undetected; for supposing this to be obvious, then the
other man will object that the point which he himself questioned has
not been discussed, but only the other point. This commonplace rule is
convertible for purposes both of establishing and of overthrowing a
view. For if we want to establish a statement, we shall show that in
one sense the attribute belongs, if we cannot show it of both
senses: whereas if we are overthrowing a statement, we shall show that
in one sense the attribute does not belong, if we cannot show it of
both senses. Of course, in overthrowing a statement there is no need
to start the discussion by securing any admission, either when the
statement asserts or when it denies the attribute universally: for
if we show that in any case whatever the attribute does not belong, we
shall have demolished the universal assertion of it, and likewise also
if we show that it belongs in a single case, we shall demolish the
universal denial of it. Whereas in establishing a statement we ought
to secure a preliminary admission that if it belongs in any case
whatever, it belongs universally, supposing this claim to be a
plausible one. For it is not enough to discuss a single instance in
order to show that an attribute belongs universally; e.g. to argue
that if the soul of man be immortal, then every soul is immortal, so