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
are in a position like that which we occupy in regard to rhetoric
and medicine and faculties of that kind: this means the doing of
that which we choose with the materials that are available. For it
is not every method that the rhetorician will employ to persuade, or
the doctor to heal; still, if he omits none of the available means, we
shall say that his grasp of the science is adequate.

                                 4

  First, then, we must see of what parts our inquiry consists. Now
if we were to grasp (a) with reference to how many, and what kind
of, things arguments take place, and with what materials they start,
and (h) how we are to become well supplied with these, we should
have sufficiently won our goal. Now the materials with which arguments
start are equal in number, and are identical, with the subjects on
which reasonings take place. For arguments start with
'propositions', while the subjects on which reasonings take place
are 'problems'. Now every proposition and every problem indicates
either a genus or a peculiarity or an accident-for the differentia
too, applying as it does to a class (or genus), should be ranked
together with the genus. Since, however, of what is peculiar to
anything part signifies its essence, while part does not, let us
divide the 'peculiar' into both the aforesaid parts, and call that
part which indicates the essence a 'definition', while of the
remainder let us adopt the terminology which is generally current
about these things, and speak of it as a 'property'. What we have
said, then, makes it clear that according to our present division, the
elements turn out to be four, all told, namely either property or
definition or genus or accident. Do not let any one suppose us to mean
that each of these enunciated by itself constitutes a proposition or
problem, but only that it is from these that both problems and
propositions are formed. The difference between a problem and a
proposition is a difference in the turn of the phrase. For if it be
put in this way, "'An animal that walks on two feet" is the definition
of man, is it not?' or '"Animal" is the genus of man, is it not?'
the result is a proposition: but if thus, 'Is "an animal that walks on
two feet" a definition of man or no?' [or 'Is "animal" his genus or
no?'] the result is a problem. Similarly too in other cases.
Naturally, then, problems and propositions are equal in number: for
out of every proposition you will make a problem if you change the
turn of the phrase.

                                 5

  We must now say what are 'definition', 'property', 'genus', and
'accident'. A 'definition' is a phrase signifying a thing's essence.
It is rendered in the form either of a phrase in lieu of a term, or of
a phrase in lieu of another phrase; for it is sometimes possible to
define the meaning of a phrase as well. People whose rendering
consists of a term only, try it as they may, clearly do not render the
definition of the thing in question, because a definition is always
a phrase of a certain kind. One may, however, use the word
'definitory' also of such a remark as 'The "becoming" is "beautiful"',
and likewise also of the question, 'Are sensation and knowledge the
same or different?', for argument about definitions is mostly
concerned with questions of sameness and difference. In a word we
may call 'definitory' everything that falls under the same branch of
inquiry as definitions; and that all the above-mentioned examples
are of this character is clear on the face of them. For if we are able
to argue that two things are the same or are different, we shall be
well supplied by the same turn of argument with lines of attack upon
their definitions as well: for when we have shown that they are not
the same we shall have demolished the definition. Observe, please,
that the converse of this last statement does not hold: for to show
that they are the same is not enough to establish a definition. To
show, however, that they are not the same is enough of itself to
overthrow it.
  A 'property' is a predicate which does not indicate the essence of a
thing, but yet belongs to that thing alone, and is predicated
convertibly of it. Thus it is a property of man to-be-capable of
learning grammar: for if A be a man, then he is capable of learning
grammar, and if he be capable of learning grammar, he is a man. For no
one calls anything a 'property' which may possibly belong to something
else, e.g. 'sleep' in the case of man, even though at a certain time
it may happen to belong to him alone. That is to say, if any such
thing were actually to be called a property, it will be called not a
'property' absolutely, but a 'temporary' or a 'relative' property: for
'being on the right hand side' is a temporary property, while
'two-footed' is in point of fact ascribed as a property in certain
relations; e.g. it is a property of man relatively to a horse and a
dog. That nothing which may belong to anything else than A is a
convertible predicate of A is clear: for it does not necessarily
follow that if something is asleep it is a man.
  A 'genus' is what is predicated in the category of essence of a
number of things exhibiting differences in kind. We should treat as
predicates in the category of essence all such things as it would be
appropriate to mention in reply to the question, 'What is the object
before you?'; as, for example, in the case of man, if asked that
question, it is appropriate to say 'He is an animal'. The question,
'Is one thing in the same genus as another or in a different one?'
is also a 'generic' question; for a question of that kind as well
falls under the same branch of inquiry as the genus: for having argued
that 'animal' is the genus of man, and likewise also of ox, we shall
have argued that they are in the same genus; whereas if we show that
it is the genus of the one but not of the other, we shall have
argued that these things are not in the same genus.
  An 'accident' is (i) something which, though it is none of the
foregoing-i.e. neither a definition nor a property nor a genus yet
belongs to the thing: (something which may possibly either belong or
not belong to any one and the self-same thing, as (e.g.) the
'sitting posture' may belong or not belong to some self-same thing.
Likewise also 'whiteness', for there is nothing to prevent the same
thing being at one time white, and at another not white. Of the
definitions of accident the second is the better: for if he adopts the
first, any one is bound, if he is to understand it, to know already
what 'definition' and 'genus' and 'property' are, whereas the second
is sufficient of itself to tell us the essential meaning of the term
in question. To Accident are to be attached also all comparisons of
things together, when expressed in language that is drawn in any
kind of way from what happens (accidit) to be true of them; such as,
for example, the question, 'Is the honourable or the expedient
preferable?' and 'Is the life of virtue or the life of self-indulgence
the pleasanter?', and any other problem which may happen to be phrased
in terms like these. For in all such cases the question is 'to which
of the two does the predicate in question happen (accidit) to belong
more closely?' It is clear on the face of it that there is nothing
to prevent an accident from becoming a temporary or relative property.
Thus the sitting posture is an accident, but will be a temporary
property, whenever a man is the only person sitting, while if he be
not the only one sitting, it is still a property relatively to those
who are not sitting. So then, there is nothing to prevent an
accident from becoming both a relative and a temporary property; but a
property absolutely it will never be.

                                 6

  We must not fail to observe that all remarks made in criticism of
a 'property' and 'genus' and 'accident' will be applicable to
'definitions' as well. For when we have shown that the attribute in
question fails to belong only to the term defined, as we do also in
the case of a property, or that the genus rendered in the definition
is not the true genus, or that any of the things mentioned in the
phrase used does not belong, as would be remarked also in the case
of an accident, we shall have demolished the definition; so that, to
use the phrase previously employed,' all the points we have enumerated
might in a certain sense be called 'definitory'. But we must not on
this account expect to find a single line of inquiry which will
apply universally to them all: for this is not an easy thing to
find, and, even were one found, it would be very obscure indeed, and
of little service for the treatise before us. Rather, a special plan
of inquiry must be laid down for each of the classes we have
distinguished, and then, starting from the rules that are
appropriate in each case, it will probably be easier to make our way
right through the task before us. So then, as was said before,' we
must outline a division of our subject, and other questions we must
relegate each to the particular branch to which it most naturally
belongs, speaking of them as 'definitory' and 'generic' questions. The
questions I mean have practically been already assigned to their
several branches.

                                 7

  First of all we must define the number of senses borne by the term
'Sameness'. Sameness would be generally regarded as falling, roughly
speaking, into three divisions. We generally apply the term
numerically or specifically or generically-numerically in cases
where there is more than one name but only one thing, e.g. 'doublet'
and 'cloak'; specifically, where there is more than one thing, but
they present no differences in respect of their species, as one man
and another, or one horse and another: for things like this that
fall under the same species are said to be 'specifically the same'.
Similarly, too, those things are called generically the same which
fall under the same genus, such as a horse and a man. It might
appear that the sense in which water from the same spring is called
'the same water' is somehow different and unlike the senses
mentioned above: but really such a case as this ought to be ranked
in the same class with the things that in one way or another are
called 'the same' in view of unity of species. For all such things
seem to be of one family and to resemble one another. For the reaon
why all water is said to be specifically the same as all other water
is because of a certain likeness it bears to it, and the only
difference in the case of water drawn from the same spring is this,
that the likeness is more emphatic: that is why we do not
distinguish it from the things that in one way or another are called
'the same' in view of unity of species. It is generally supposed
that the term 'the same' is most used in a sense agreed on by every
one when applied to what is numerically one. But even so, it is apt to
be rendered in more than one sense; its most literal and primary use
is found whenever the sameness is rendered in reference to an
alternative name or definition, as when a cloak is said to be the same
as a doublet, or an animal that walks on two feet is said to be the
same as a man: a second sense is when it is rendered in reference to a
property, as when what can acquire knowledge is 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.

                                 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.

                                 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.

                                10

  First, then, a definition must be given of a 'dialectical
proposition' and a 'dialectical problem'. For it is not every
proposition nor yet every problem that is to be set down as
dialectical: for no one in his senses would make a proposition of what
no one holds, nor yet make a problem of what is obvious to everybody
or to most people: for the latter admits of no doubt, while to the
former no one would assent. Now a dialectical proposition consists
in asking something that is held by all men or by most men or by the
philosophers, i.e. either by all, or by most, or by the most notable
of these, provided it be not contrary to the general opinion; for a
man would probably assent to the view of the philosophers, if it be
not contrary to the opinions of most men. Dialectical propositions
also include views which are like those generally accepted; also
propositions which contradict the contraries of opinions that are
taken to be generally accepted, and also all opinions that are in
accordance with the recognized arts. Thus, supposing it to be a
general opinion that the knowledge of contraries is the same, it might
probably pass for a general opinion also that the perception of
contraries is the same: also, supposing it to be a general opinion
that there is but one single science of grammar, it might pass for a
general opinion that there is but one science of flute-playing as
well, whereas, if it be a general opinion that there is more than
one science of grammar, it might pass for a general opinion that there
is more than one science of flute-playing as well: for all these
seem to be alike and akin. Likewise, also, propositions
contradicting the contraries of general opinions will pass as
general opinions: for if it be a general opinion that one ought to
do good to one's friends, it will also be a general opinion that one
ought not to do them harm. Here, that one ought to do harm to one's
friends is contrary to the general view, and that one ought not to
do them harm is the contradictory of that contrary. Likewise also,
if one ought to do good to one's friends, one ought not to do good
to one's enemies: this too is the contradictory of the view contrary
to the general view; the contrary being that one ought to do good to
one's enemies. Likewise, also, in other cases. Also, on comparison, it
will look like a general opinion that the contrary predicate belongs
to the contrary subject: e.g. if one ought to do good to one's
friends, one ought also to do evil to one's enemies. it might appear
also as if doing good to one's friends were a contrary to doing evil
to one's enemies: but whether this is or is not so in reality as
well will be stated in the course of the discussion upon contraries.
Clearly also, all opinions that are in accordance with the arts are
dialectical propositions; for people are likely to assent to the views
held by those who have made a study of these things, e.g. on a
question of medicine they will agree with the doctor, and on a
question of geometry with the geometrician; and likewise also in other
cases.

                                11

  A dialectical problem is a subject of inquiry that contributes
either to choice and avoidance, or to truth and knowledge, and that
either by itself, or as a help to the solution of some other such
problem. It must, moreover, be something on which either people hold
no opinion either way, or the masses hold a contrary opinion to the
philosophers, or the philosophers to the masses, or each of them among
themselves. For some problems it is useful to know with a view to
choice or avoidance, e.g. whether pleasure is to be chosen or not,
while some it is useful to know merely with a view to knowledge,
e.g. whether the universe is eternal or not: others, again, are not
useful in and by themselves for either of these purposes, but yet help
us in regard to some such problems; for there are many things which we
do not wish to know in and by themselves, but for the sake of other
things, in order that through them we may come to know something else.
Problems also include questions in regard to which reasonings conflict
(the difficulty then being whether so-and so is so or not, there being
convincing arguments for both views); others also in regard to which
we have no argument because they are so vast, and we find it difficult
to give our reasons, e.g. the question whether the universe is eternal
or no: for into questions of that kind too it is possible to inquire.
  Problems, then, and propositions are to be defined as aforesaid. A
'thesis' is a supposition of some eminent philosopher that conflicts
with the general opinion; e.g. the view that contradiction is
impossible, as Antisthenes said; or the view of Heraclitus that all
things are in motion; or that Being is one, as Melissus says: for to
take notice when any ordinary person expresses views contrary to men's
usual opinions would be silly. Or it may be a view about which we have
a reasoned theory contrary to men's usual opinions, e.g. the view
maintained by the sophists that what is need not in every case
either have come to be or be eternal: for a musician who is a
grammarian 'is' so without ever having 'come to be' so, or being so
eternally. For even if a man does not accept this view, he might do so
on the ground that it is reasonable.
  Now a 'thesis' also is a problem, though a problem is not always a
thesis, inasmuch as some problems are such that we have no opinion
about them either way. That a thesis, however, also forms a problem,
is clear: for it follows of necessity from what has been said that
either the mass of men disagree with the philosophers about the
thesis, or that the one or the other class disagree among
themselves, seeing that the thesis is a supposition in conflict with
general opinion. Practically all dialectical problems indeed are now
called 'theses'. But it should make no difference whichever
description is used; for our object in thus distinguishing them has
not been to create a terminology, but to recognize what differences
happen to be found between them.
  Not every problem, nor every thesis, should be examined, but only
one which might puzzle one of those who need argument, not
punishment or perception. For people who are puzzled to know whether
one ought to honour the gods and love one's parents or not need
punishment, while those who are puzzled to know whether snow is
white or not need perception. The subjects should not border too
closely upon the sphere of demonstration, nor yet be too far removed
from it: for the former cases admit of no doubt, while the latter
involve difficulties too great for the art of the trainer.

                                12

  Having drawn these definitions, we must distinguish how many species
there are of dialectical arguments. There is on the one hand
Induction, on the other Reasoning. Now what reasoning is has been said
before: induction is a passage from individuals to universals, e.g.
the argument that supposing the skilled pilot is the most effective,
and likewise the skilled charioteer, then in general the skilled man
is the best at his particular task. Induction is the more convincing
and clear: it is more readily learnt by the use of the senses, and
is applicable generally to the mass of men, though reasoning is more
forcible and effective against contradictious people.

                                13

  The classes, then, of things about which, and of things out of
which, arguments are constructed, are to be distinguished in the way
we have said before. The means whereby we are to become well
supplied with reasonings are four: (1) the securing of propositions;
(2) the power to distinguish in how many senses particular
expression is used; (3) the discovery of the differences of things;
(4) the investigation of likeness. The last three, as well, are in a
certain sense propositions: for it is possible to make a proposition
corresponding to each of them, e.g. (1) 'The desirable may mean either
the honourable or the pleasant or the expedient'; and (2) Sensation
differs from knowledge in that the latter may be recovered again after
it has been lost, while the former cannot'; and (3) The relation of
the healthy to health is like that of the vigorous to vigour'. The
first proposition depends upon the use of one term in several
senses, the second upon the differences of things, the third upon
their likenesses.

                                14

  Propositions should be selected in a number of ways corresponding to
the number of distinctions drawn in regard to the proposition: thus
one may first take in hand the opinions held by all or by most men
or by the philosophers, i.e. by all, or most, or the most notable of
them; or opinions contrary to those that seem to be generally held;
and, again, all opinions that are in accordance with the arts. We must
make propositions also of the contradictories of opinions contrary
to those that seem to be generally held, as was laid down before. It
is useful also to make them by selecting not only those opinions
that actually are accepted, but also those that are like these, e.g.
'The perception of contraries is the same'-the knowledge of them being
so-and 'we see by admission of something into ourselves, not by an
emission'; for so it is, too, in the case of the other senses; for
in hearing we admit something into ourselves; we do not emit; and we
taste in the same way. Likewise also in the other cases. Moreover, all
statements that seem to be true in all or in most cases, should be
taken as a principle or accepted position; for they are posited by
those who do not also see what exception there may be. We should
select also from the written handbooks of argument, and should draw up
sketch-lists of them upon each several kind of subject, putting them
down under separate headings, e.g. 'On Good', or 'On Life'-and that
'On Good' should deal with every form of good, beginning with the
category of essence. In the margin, too, one should indicate also
the opinions of individual thinkers, e.g. 'Empedocles said that the
elements of bodies were four': for any one might assent to the
saying of some generally accepted authority.
  Of propositions and problems there are-to comprehend the matter in
outline-three divisions: for some are ethical propositions, some are
on natural philosophy, while some are logical. Propositions such as
the following are ethical, e.g. 'Ought one rather to obey one's
parents or the laws, if they disagree?'; such as this are logical,
e.g. 'Is the knowledge of opposites the same or not?'; while such as
this are on natural philosophy, e.g. 'Is the universe eternal or not?'
Likewise also with problems. The nature of each of the aforesaid kinds
of proposition is not easily rendered in a definition, but we have
to try to recognize each of them by means of the familiarity
attained through induction, examining them in the light of the
illustrations given above.
  For purposes of philosophy we must treat of these things according
to their truth, but for dialectic only with an eye to general opinion.
All propositions should be taken in their most universal form; then,
the one should be made into many. E.g. 'The knowledge of opposites
is the same'; next, 'The knowledge of contraries is the same', and
that 'of relative terms'. In the same way these two should again be
divided, as long as division is possible, e.g. the knowledge of
'good and evil', of 'white and black', or 'cold and hot'. Likewise
also in other cases.

                                15

  On the formation, then, of propositions, the above remarks are
enough. As regards the number of senses a term bears, we must not only
treat of those terms which bear different senses, but we must also try
to render their definitions; e.g. we must not merely say that
justice and courage are called 'good' in one sense, and that what
conduces to vigour and what conduces to health are called so in
another, but also that the former are so called because of a certain
intrinsic quality they themselves have, the latter because they are
productive of a certain result and not because of any intrinsic
quality in themselves. Similarly also in other cases.
  Whether a term bears a number of specific meanings or one only,
may be considered by the following means. First, look and see if its
contrary bears a number of meanings, whether the discrepancy between
them be one of kind or one of names. For in some cases a difference is
at once displayed even in the names; e.g. the contrary of 'sharp' in
the case of a note is 'flat', while in the case of a solid edge it
is 'dull'. Clearly, then, the contrary of 'sharp' bears several
meanings, and if so, also does 'sharp'; for corresponding to each of
the former terms the meaning of its contrary will be different. For
'sharp' will not be the same when contrary to 'dull' and to 'flat',
though 'sharp' is the contrary of each. Again Barhu ('flat',
'heavy') in the case of a note has 'sharp' as its contrary, but in the
case of a solid mass 'light', so that Barhu is used with a number of
meanings, inasmuch as its contrary also is so used. Likewise, also,
'fine' as applied to a picture has 'ugly' as its contrary, but, as
applied to a house, 'ramshackle'; so that 'fine' is an ambiguous term.
  In some cases there is no discrepancy of any sort in the names used,
but a difference of kind between the meanings is at once obvious: e.g.
in the case of 'clear' and 'obscure': for sound is called 'clear'
and 'obscure', just as 'colour' is too. As regards the names, then,
there is no discrepancy, but the difference in kind between the
meanings is at once obvious: for colour is not called 'clear' in a
like sense to sound. This is plain also through sensation: for of
things that are the same in kind we have the same sensation, whereas
we do not judge clearness by the same sensation in the case of sound
and of colour, but in the latter case we judge by sight, in the former
by hearing. Likewise also with 'sharp' and 'dull' in regard to
flavours and solid edges: here in the latter case we judge by touch,
but in the former by taste. For here again there is no discrepancy
in the names used, in the case either of the original terms or of
their contraries: for the contrary also of sharp in either sense is
'dull'.
  Moreover, see if one sense of a term has a contrary, while another
has absolutely none; e.g. the pleasure of drinking has a contrary in
the pain of thirst, whereas the pleasure of seeing that the diagonal
is incommensurate with the side has none, so that 'pleasure' is used
in more than one sense. To 'love' also, used of the frame of mind, has
to 'hate' as its contrary, while as used of the physical activity
(kissing) it has none: clearly, therefore, to 'love' is an ambiguous
term. Further, see in regard to their intermediates, if some
meanings and their contraries have an intermediate, others have
none, or if both have one but not the same one, e.g. 'clear' and
'obscure' in the case of colours have 'grey' as an intermediate,
whereas in the case of sound they have none, or, if they have, it is
'harsh', as some people say that a harsh sound is intermediate.
'Clear', then, is an ambiguous term, and likewise also 'obscure'. See,
moreover, if some of them have more than one intermediate, while
others have but one, as is the case with 'clear' and 'obscure', for in
the case of colours there are numbers of intermediates, whereas in
regard to sound there is but one, viz. 'harsh'.
  Again, in the case of the contradictory opposite, look and see if it
bears more than one meaning. For if this bears more than one
meaning, then the opposite of it also will be used in more than one
meaning; e.g. 'to fail to see' a phrase with more than one meaning,
viz. (1) to fail to possess the power of sight, (2) to fail to put
that power to active use. But if this has more than one meaning, it
follows necessarily that 'to see' also has more than one meaning:
for there will be an opposite to each sense of 'to fail to see';
e.g. the opposite of 'not to possess the power of sight' is to possess
it, while of 'not to put the power of sight to active use', the
opposite is to put it to active use.
  Moreover, examine the case of terms that denote the privation or
presence of a certain state: for if the one term bears more than one
meaning, then so will the remaining term: e.g. if 'to have sense' be
used with more than one meaning, as applied to the soul and to the
body, then 'to be wanting in sense' too will be used with more than
one meaning, as applied to the soul and to the body. That the
opposition between the terms now in question depends upon the
privation or presence of a certain state is clear, since animals
naturally possess each kind of 'sense', both as applied to the soul
and as applied to the body.
  Moreover, examine the inflected forms. For if 'justly' has more than
one meaning, then 'just', also, will be used with more than one
meaning; for there will be a meaning of 'just' to each of the meanings
of 'justly'; e.g. if the word 'justly' be used of judging according to
one's own opinion, and also of judging as one ought, then 'just'
also will be used in like manner. In the same way also, if 'healthy'
has more than one meaning, then 'healthily' also will be used with
more than one meaning: e.g. if 'healthy' describes both what
produces health and what preserves health and what betokens health,
then 'healthily' also will be used to mean 'in such a way as to
produce' or 'preserve' or 'betoken' health. Likewise also in other
cases, whenever the original term bears more than one meaning, the
inflexion also that is formed from it will be used with more than
one meaning, and vice versa.
  Look also at the classes of the predicates signified by the term,
and see if they are the same in all cases. For if they are not the
same, then clearly the term is ambiguous: e.g. 'good' in the case of
food means 'productive of pleasure', and in the case of medicine
'productive of health', whereas as applied to the soul it means to
be of a certain quality, e.g. temperate or courageous or just: and
likewise also, as applied to 'man'. Sometimes it signifies what
happens at a certain time, as (e.g.) the good that happens at the
right time: for what happens at the right time is called good. Often
it signifies what is of certain quantity, e.g. as applied to the
proper amount: for the proper amount too is called good. So then the
term 'good' is ambiguous. In the same way also 'clear', as applied
to a body, signifies a colour, but in regard to a note it denotes what
is 'easy to hear'. 'Sharp', too, is in a closely similar case: for the
same term does not bear the same meaning in all its applications:
for a sharp note is a swift note, as the mathematical theorists of
harmony tell us, whereas a sharp (acute) angle is one that is less
than a right angle, while a sharp dagger is one containing a sharp
angle (point).
  Look also at the genera of the objects denoted by the same term, and
see if they are different without being subaltern, as (e.g.) 'donkey',
which denotes both the animal and the engine. For the definition of
them that corresponds to the name is different: for the one will be
declared to be an animal of a certain kind, and the other to be an
engine of a certain kind. If, however, the genera be subaltern,
there is no necessity for the definitions to be different. Thus (e.g.)
'animal' is the genus of 'raven', and so is 'bird'. Whenever therefore
we say that the raven is a bird, we also say that it is a certain kind
of animal, so that both the genera are predicated of it. Likewise also
whenever we call the raven a 'flying biped animal', we declare it to
be a bird: in this way, then, as well, both the genera are
predicated of raven, and also their definition. But in the case of
genera that are not subaltern this does not happen, for whenever we
call a thing an 'engine', we do not call it an animal, nor vice versa.
  Look also and see not only if the genera of the term before you
are different without being subaltern, but also in the case of its
contrary: for if its contrary bears several senses, clearly the term
before you does so as well.
  It is useful also to look at the definition that arises from the use
of the term in combination, e.g. of a 'clear (lit. white) body' of a
'clear note'. For then if what is peculiar in each case be abstracted,
the same expression ought to remain over. This does not happen in
the case of ambiguous terms, e.g. in the cases just mentioned. For the
former will be body possessing such and such a colour', while the
latter will be 'a note easy to hear'. Abstract, then, 'a body 'and'
a note', and the remainder in each case is not the same. It should,
however, have been had the meaning of 'clear' in each case been
synonymous.
  Often in the actual definitions as well ambiguity creeps in
unawares, and for this reason the definitions also should be examined.
If (e.g.) any one describes what betokens and what produces health
as 'related commensurably to health', we must not desist but go on
to examine in what sense he has used the term 'commensurably' in
each case, e.g. if in the latter case it means that 'it is of the
right amount to produce health', whereas in the for it means that
'it is such as to betoken what kind of state prevails'.
  Moreover, see if the terms cannot be compared as 'more or less' or
as 'in like manner', as is the case (e.g.) with a 'clear' (lit. white)
sound and a 'clear' garment, and a 'sharp' flavour and a 'sharp' note.
For neither are these things said to be clear or sharp 'in a like
degree', nor yet is the one said to be clearer or sharper than the
other. 'Clear', then, and 'sharp' are ambiguous. For synonyms are
always comparable; for they will always be used either in like manner,
or else in a greater degree in one case.
  Now since of genera that are different without being subaltern the
differentiae also are different in kind, e.g. those of 'animal' and
'knowledge' (for the differentiae of these are different), look and
see if the meanings comprised under the same term are differentiae
of genera that are different without being subaltern, as e.g.
'sharp' is of a 'note' and a 'solid'. For being 'sharp' differentiates
note from note, and likewise also one solid from another. 'Sharp',
then, is an ambiguous term: for it forms differentiae of genera that
are different without being subaltern.
  Again, see if the actual meanings included under the same term
themselves have different differentiae, e.g. 'colour' in bodies and
'colour' in tunes: for the differentiae of 'colour' in bodies are
'sight-piercing' and 'sight compressing', whereas 'colour' in melodies
has not the same differentiae. Colour, then, is an ambiguous term; for
things that are the same have the same differentiae.
  Moreover, since the species is never the differentia of anything,
look and see if one of the meanings included under the same term be
a species and another a differentia, as (e.g.) clear' (lit. white)
as applied to a body is a species of colour, whereas in the case of
a note it is a differentia; for one note is differentiated from
another by being 'clear'.

                                16

  The presence, then, of a number of meanings in a term may be
investigated by these and like means. The differences which things
present to each other should be examined within the same genera,
e.g. 'Wherein does justice differ from courage, and wisdom from
temperance?'-for all these belong to the same genus; and also from one
genus to another, provided they be not very much too far apart, e.g.
'Wherein does sensation differ from knowledge?: for in the case of
genera that are very far apart, the differences are entirely obvious.

                                17

  Likeness should be studied, first, in the case of things belonging
to different genera, the formulae being 'A:B = C:D' (e.g. as knowledge
stands to the object of knowledge, so is sensation related to the
object of sensation), and 'As A is in B, so is C in D' (e.g. as
sight is in the eye, so is reason in the soul, and as is a calm in the
sea, so is windlessness in the air). Practice is more especially
needed in regard to terms that are far apart; for in the case of the
rest, we shall be more easily able to see in one glance the points
of likeness. We should also look at things which belong to the same
genus, to see if any identical attribute belongs to them all, e.g.
to a man and a horse and a dog; for in so far as they have any
identical attribute, in so far they are alike.

                                18

  It is useful to have examined the number of meanings of a term
both for clearness' sake (for a man is more likely to know what it
is he asserts, if it bas been made clear to him how many meanings it
may have), and also with a view to ensuring that our reasonings
shall be in accordance with the actual facts and not addressed
merely to the term used. For as long as it is not clear in how many
senses a term is used, it is possible that the answerer and the
questioner are not directing their minds upon the same thing:
whereas when once it has been made clear how many meanings there
are, and also upon which of them the former directs his mind when he
makes his assertion, the questioner would then look ridiculous if he
failed to address his argument to this. It helps us also both to avoid
being misled and to mislead by false reasoning: for if we know the
number of meanings of a term, we shall certainly never be misled by
false reasoning, but shall know if the questioner fails to address his
argument to the same point; and when we ourselves put the questions we
shall be able to mislead him, if our answerer happens not to know
the number of meanings of our terms. This, however, is not possible in
all cases, but only when of the many senses some are true and others
are false. This manner of argument, however, does not belong
properly to dialectic; dialecticians should therefore by all means
beware of this kind of verbal discussion, unless any one is absolutely
unable to discuss the subject before him in any other way.
  The discovery of the differences of things helps us both in
reasonings about sameness and difference, and also in recognizing what
any particular thing is. That it helps us in reasoning about
sameness and difference is clear: for when we have discovered a
difference of any kind whatever between the objects before us, we
shall already have shown that they are not the same: while it helps us
in recognizing what a thing is, because we usually distinguish the
expression that is proper to the essence of each particular thing by
means of the differentiae that are proper to it.
  The examination of likeness is useful with a view both to
inductive arguments and to hypothetical reasonings, and also with a
view to the rendering of definitions. It is useful for inductive
arguments, because it is by means of an induction of individuals in
cases that are alike that we claim to bring the universal in evidence:
for it is not easy to do this if we do not know the points of
likeness. It is useful for hypothetical reasonings because it is a
general opinion that among similars what is true of one is true also
of the rest. If, then, with regard to any of them we are well supplied
with matter for a discussion, we shall secure a preliminary
admission that however it is in these cases, so it is also in the case
before us: then when we have shown the former we shall have shown,
on the strength of the hypothesis, the matter before us as well: for
we have first made the hypothesis that however it is in these cases,
so it is also in the case before us, and have then proved the point as
regards these cases. It is useful for the rendering of definitions
because, if we are able to see in one glance what is the same in
each individual case of it, we shall be at no loss into what genus
we ought to put the object before us when we define it: for of the
common predicates that which is most definitely in the category of
essence is likely to be the genus. Likewise, also, in the case of
objects widely divergent, the examination of likeness is useful for
purposes of definition, e.g. the sameness of a calm at sea, and
windlessness in the air (each being a form of rest), and of a point on
a line and the unit in number-each being a starting point. If, then,
we render as the genus what is common to all the cases, we shall get
the credit of defining not inappropriately. Definition-mongers too
nearly always render them in this way: they declare the unit to be the
startingpoint of number, and the point the startingpoint of a line. It
is clear, then, that they place them in that which is common to both
as their genus.
  The means, then, whereby reasonings are effected, are these: the
commonplace rules, for the observance of which the aforesaid means are
useful, are as follows.

                              Book II
                                 1

  Of problems some are universal, others particular. Universal
problems are such as 'Every pleasure is good' and 'No pleasure is
good'; particular problems are such as 'Some pleasure is good' and
'Some pleasure is not good'. The methods of establishing and
overthrowing a view universally are common to both kinds of
problems; for when we have shown that a predicate belongs in every
case, we shall also have shown that it belongs in some cases.
Likewise, also, if we show that it does not belong in any case, we
shall also have shown that it does not belong in every case. First,
then, we must speak of the methods of overthrowing a view universally,
because such are common to both universal and particular problems, and
because people more usually introduce theses asserting a predicate
than denying it, while those who argue with them overthrow it. The
conversion of an appropriate name which is drawn from the element
'accident' is an extremely precarious thing; for in the case of
accidents and in no other it is possible for something to be true
conditionally and not universally. Names drawn from the elements
'definition' and 'property' and 'genus' are bound to be convertible;
e.g. if 'to be an animal that walks on two feet is an attribute of S',
then it will be true by conversion to say that 'S is an animal that
walks on two feet'. Likewise, also, if drawn from the genus; for if
'to be an animal is an attribute of S', then 'S is an animal'. The
same is true also in the case of a property; for if 'to be capable
of learning grammar is an attribute of S', then 'S will be capable
of learning grammar'. For none of these attributes can possibly belong
or not belong in part; they must either belong or not belong
absolutely. In the case of accidents, on the other hand, there is
nothing to prevent an attribute (e.g. whiteness or justice)
belonging in part, so that it is not enough to show that whiteness
or justice is an attribute of a man in order to show that he is
white or just; for it is open to dispute it and say that he is white
or just in part only. Conversion, then, is not a necessary process
in the case of accidents.
  We must also define the errors that occur in problems. They are of
two kinds, caused either by false statement or by transgression of the
established diction. For those who make false statements, and say that
an attribute belongs to thing which does not belong to it, commit
error; and those who call objects by the names of other objects
(e.g. calling a planetree a 'man') transgress the established
terminology.

                                 2

  Now one commonplace rule is to look and see if a man has ascribed as
an accident what belongs in some other way. This mistake is most
commonly made in regard to the genera of things, e.g. if one were to
say that white happens (accidit) to be a colour-for being a colour
does not happen by accident to white, but colour is its genus. The
assertor may of course define it so in so many words, saying (e.g.)
that 'Justice happens (accidit) to be a virtue'; but often even
without such definition it is obvious that he has rendered the genus
as an accident; e.g. suppose that one were to say that whiteness is
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
that a previous admission must be secured that if any soul whatever be
immortal, then every soul is immortal. This is not to be done in every
case, but only whenever we are not easily able to quote any single
argument applying to all cases in common, as (e.g.) the geometrician
can argue that the triangle has its angles equal to two right angles.
  If, again, the variety of meanings of a term be obvious, distinguish
how many meanings it has before proceeding either to demolish or to
establish it: e.g. supposing 'the right' to mean 'the expedient' or
'the honourable', you should try either to establish or to demolish
both descriptions of the subject in question; e.g. by showing that
it is honourable and expedient, or that it is neither honourable nor
expedient. Supposing, however, that it is impossible to show both, you
should show the one, adding an indication that it is true in the one
sense and not in the other. The same rule applies also when the number
of senses into which it is divided is more than two.
  Again, consider those expressions whose meanings are many, but
differ not by way of ambiguity of a term, but in some other way:
e.g. 'The science of many things is one': here 'many things' may
mean the end and the means to that end, as (e.g.) medicine is the
science both of producing health and of dieting; or they may be both
of them ends, as the science of contraries is said to be the same (for
of contraries the one is no more an end than the other); or again they
may be an essential and an accidental attribute, as (e.g.) the
essential fact that the triangle has its angles equal to two right
angles, and the accidental fact that the equilateral figure has them
so: for it is because of the accident of the equilateral triangle
happening to be a triangle that we know that it has its angles equal
to two right angles. If, then, it is not possible in any sense of
the term that the science of many things should be the same, it
clearly is altogether impossible that it should be so; or, if it is
possible in some sense, then clearly it is possible. Distinguish as
many meanings as are required: e.g. if we want to establish a view, we
should bring forward all such meanings as admit that view and should
divide them only into those meanings which also are required for the
establishment of our case: whereas if we want to overthrow a view,
we should bring forward all that do not admit that view, and leave the
rest aside. We must deal also in these cases as well with any
uncertainty about the number of meanings involved. Further, that one
thing is, or is not, 'of' another should be established by means of
the same commonplace rules; e.g. that a particular science is of a
particular thing, treated either as an end or as a means to its end,
or as accidentally connected with it; or again that it is not 'of'
it in any of the aforesaid ways. The same rule holds true also of
desire and all other terms that have more than one object. For the
'desire of X' may mean the desire of it as an end (e.g. the desire
of health) or as a means to an end (e.g. the desire of being
doctored), or as a thing desired accidentally, as, in the case of
wine, the sweet-toothed person desires it not because it is wine but
because it is sweet. For essentially he desires the sweet, and only
accidentally the wine: for if it be dry, he no longer desires it.
His desire for it is therefore accidental. This rule is useful in
dealing with relative terms: for cases of this kind are generally
cases of relative terms.

                                 4

  Moreover, it is well to alter a term into one more familiar, e.g. to
substitute 'clear' for 'exact' in describing a conception, and
'being fussy' for 'being busy': for when the expression is made more
familiar, the thesis becomes easier to attack. This commonplace rule
also is available for both purposes alike, both for establishing and
for overthrowing a view.
  In order to show that contrary attributes belong to the same
thing, look at its genus; e.g. if we want to show that rightness and
wrongness are possible in regard to perception, and to perceive is
to judge, while it is possible to judge rightly or wrongly, then in
regard to perception as well rightness and wrongness must be possible.
In the present instance the proof proceeds from the genus and
relates to the species: for 'to judge' is the genus of 'to -perceive';
for the man who perceives judges in a certain way. But per contra it
may proceed from the species to the genus: for all the attributes that
belong to the species belong to the genus as well; e.g. if there is
a bad and a good knowledge there is also a bad and a good disposition:
for 'disposition' is the genus of knowledge. Now the former
commonplace argument is fallacious for purposes of establishing a
view, while the second is true. For there is no necessity that all the
attributes that belong to the genus should belong also to the species;
for 'animal' is flying and quadruped, but not so 'man'. All the
attributes, on the other hand, that belong to the species must of
necessity belong also to the genus; for if 'man' is good, then
animal also is good. On the other hand, for purposes of overthrowing a
view, the former argument is true while the latter is fallacious;
for all the attributes which do not belong to the genus do not
belong to the species either; whereas all those that are wanting to
the species are not of necessity wanting to the genus.
  Since those things of which the genus is predicated must also of
necessity have one of its species predicated of them, and since
those things that are possessed of the genus in question, or are
described by terms derived from that genus, must also of necessity
be possessed of one of its species or be described by terms derived
from one of its species (e.g. if to anything the term 'scientific
knowledge' be applied, then also there will be applied to it the
term 'grammatical' or 'musical' knowledge, or knowledge of one of
the other sciences; and if any one possesses scientific knowledge or
is described by a term derived from 'science', then he will also
possess grammatical or musical knowledge or knowledge of one of the
other sciences, or will be described by a term derived from one of
them, e.g. as a 'grammarian' or a 'musician')-therefore if any
expression be asserted that is in any way derived from the genus (e.g.
that the soul is in motion), look and see whether it be possible for
the soul to be moved with any of the species of motion; whether (e.g.)
it can grow or be destroyed or come to be, and so forth with all the
other species of motion. For if it be not moved in any of these
ways, clearly it does not move at all. This commonplace rule is common
for both purposes, both for overthrowing and for establishing a
view: for if the soul moves with one of the species of motion, clearly
it does move; while if it does not move with any of the species of
motion, clearly it does not move.
  If you are not well equipped with an argument against the assertion,
look among the definitions, real or apparent, of the thing before you,
and if one is not enough, draw upon several. For it will be easier
to attack people when committed to a definition: for an attack is
always more easily made on definitions.
  Moreover, look and see in regard to the thing in question, what it
is whose reality conditions the reality of the thing in question, or
what it is whose reality necessarily follows if the thing in
question be real: if you wish to establish a view inquire what there
is on whose reality the reality of the thing in question will follow
(for if the former be shown to be real, then the thing in question
will also have been shown to be real); while if you want to
overthrow a view, ask what it is that is real if the thing in question
be real, for if we show that what follows from the thing in question
is unreal, we shall have demolished the thing in question.
  Moreover, look at the time involved, to see if there be any
discrepancy anywhere: e.g. suppose a man to have stated that what is
being nourished of necessity grows: for animals are always of
necessity being nourished, but they do not always grow. Likewise,
also, if he has said that knowing is remembering: for the one is
concerned with past time, whereas the other has to do also with the
present and the future. For we are said to know things present and
future (e.g. that there will be an eclipse), whereas it is
impossible to remember anything save what is in the past.

                                 5

  Moreover, there is the sophistic turn of argument, whereby we draw
our opponent into the kind of statement against which we shall be well
supplied with lines of argument. This process is sometimes a real
necessity, sometimes an apparent necessity, sometimes neither an
apparent nor a real necessity. It is really necessary whenever the
answerer has denied any view that would be useful in attacking the
thesis, and the questioner thereupon addresses his arguments to the
support of this view, and when moreover the view in question happens
to be one of a kind on which he has a good stock of lines of argument.
Likewise, also, it is really necessary whenever he (the questioner)
first, by an induction made by means of the view laid down, arrives at
a certain statement and then tries to demolish that statement: for
when once this has been demolished, the view originally laid down is
demolished as well. It is an apparent necessity, when the point to
which the discussion comes to be directed appears to be useful, and
relevant to the thesis, without being really so; whether it be that
the man who is standing up to the argument has refused to concede
something, or whether he (the questioner) has first reached it by a
plausible induction based upon the thesis and then tries to demolish
it. The remaining case is when the point to which the discussion comes
to be directed is neither really nor apparently necessary, and it is
the answerer's luck to be confuted on a mere side issue You should
beware of the last of the aforesaid methods; for it appears to be
wholly disconnected from, and foreign to, the art of dialectic. For
this reason, moreover, the answerer should not lose his temper, but
assent to those statements that are of no use in attacking the thesis,
adding an indication whenever he assents although he does not agree
with the view. For, as a rule, it increases the confusion of
questioners if, after all propositions of this kind have been
granted them, they can then draw no conclusion.
  Moreover, any one who has made any statement whatever has in a
certain sense made several statements, inasmuch as each statement
has a number of necessary consequences: e.g. the man who said 'X is
a man' has also said that it is an animal and that it is animate and a
biped and capable of acquiring reason and knowledge, so that by the
demolition of any single one of these consequences, of whatever
kind, the original statement is demolished as well. But you should
beware here too of making a change to a more difficult subject: for
sometimes the consequence, and sometimes the original thesis, is the
easier to demolish.

                                 6

  In regard to subjects which must have one and one only of two
predicates, as (e.g.) a man must have either a disease or health,
supposing we are well supplied as regards the one for arguing its
presence or absence, we shall be well equipped as regards the
remaining one as well. This rule is convertible for both purposes: for
when we have shown that the one attribute belongs, we shall have shown
that the remaining one does not belong; while if we show that the
one does not belong, we shall have shown that the remaining one does
belong. Clearly then the rule is useful for both purposes.
  Moreover, you may devise a line of attack by reinterpreting a term
in its literal meaning, with the implication that it is most fitting
so to take it rather than in its established meaning: e.g. the
expression 'strong at heart' will suggest not the courageous man,
according to the use now established, but the man the state of whose
heart is strong; just as also the expression 'of a good hope' may be
taken to mean the man who hopes for good things. Likewise also
'well-starred' may be taken to mean the man whose star is good, as
Xenocrates says 'well-starred is he who has a noble soul'.' For a
man's star is his soul.
  Some things occur of necessity, others usually, others however it
may chance; if therefore a necessary event has been asserted to
occur usually, or if a usual event (or, failing such an event
itself, its contrary) has been stated to occur of necessity, it always
gives an opportunity for attack. For if a necessary event has been
asserted to occur usually, clearly the speaker has denied an attribute
to be universal which is universal, and so has made a mistake: and
so he has if he has declared the usual attribute to be necessary:
for then he declares it to belong universally when it does not so
belong. Likewise also if he has declared the contrary of what is usual
to be necessary. For the contrary of a usual attribute is always a
comparatively rare attribute: e.g. if men are usually bad, they are
comparatively seldom good, so that his mistake is even worse if he has
declared them to be good of necessity. The same is true also if he has
declared a mere matter of chance to happen of necessity or usually;
for a chance event happens neither of necessity nor usually. If the
thing happens usually, then even supposing his statement does not
distinguish whether he meant that it happens usually or that it
happens necessarily, it is open to you to discuss it on the assumption
that he meant that it happens necessarily: e.g. if he has stated
without any distinction that disinherited persons are bad, you may
assume in discussing it that he means that they are so necessarily.
  Moreover, look and see also if he has stated a thing to be an
accident of itself, taking it to be a different thing because it has a
different name, as Prodicus used to divide pleasures into joy and
delight and good cheer: for all these are names of the same thing,
to wit, Pleasure. If then any one says that joyfulness is an
accidental attribute of cheerfulness, he would be declaring it to be
an accidental attribute of itself.

                                 7

  Inasmuch as contraries can be conjoined with each other in six ways,
and four of these conjunctions constitute a contrariety, we must grasp
the subject of contraries, in order that it may help us both in
demolishing and in establishing a view. Well then, that the modes of
conjunction are six is clear: for either (1) each of the contrary
verbs will be conjoined to each of the contrary objects; and this
gives two modes: e.g. to do good to friends and to do evil to enemies,
or per contra to do evil to friends and to do good to enemies. Or else
(2) both verbs may be attached to one object; and this too gives two
modes, e.g. to do good to friends and to do evil to friends, or to
do good to enemies and to do evil to enemies. Or (3) a single verb may
be attached to both objects: and this also gives two modes; e.g. to do
good to friends and to do good to enemies, or to do evil to friends
and evil to enemies.
  The first two then of the aforesaid conjunctions do not constitute
any contrariety; for the doing of good to friends is not contrary to
the doing of evil to enemies: for both courses are desirable and
belong to the same disposition. Nor is the doing of evil to friends
contrary to the doing of good to enemies: for both of these are
objectionable and belong to the same disposition: and one
objectionable thing is not generally thought to be the contrary of
another, unless the one be an expression denoting an excess, and the
other an expression denoting a defect: for an excess is generally
thought to belong to the class of objectionable things, and likewise
also a defect. But the other four all constitute a contrariety. For to
do good to friends is contrary to the doing of evil to friends: for it
proceeds from the contrary disposition, and the one is desirable,
and the other objectionable. The case is the same also in regard to
the other conjunctions: for in each combination the one course is
desirable, and the other objectionable, and the one belongs to a
reasonable disposition and the other to a bad. Clearly, then, from
what has been said, the same course has more than one contrary. For
the doing of good to friends has as its contrary both the doing of
good to enemies and the doing of evil to friends. Likewise, if we
examine them in the same way, we shall find that the contraries of
each of the others also are two in number. Select therefore
whichever of the two contraries is useful in attacking the thesis.
  Moreover, if the accident of a thing have a contrary, see whether it
belongs to the subject to which the accident in question has been
declared to belong: for if the latter belongs the former could not
belong; for it is impossible that contrary predicates should belong at
the same time to the same thing.
  Or again, look and see if anything has been said about something, of
such a kind that if it be true, contrary predicates must necessarily
belong to the thing: e.g. if he has said that the 'Ideas' exist in us.
For then the result will be that they are both in motion and at
rest, and moreover that they are objects both of sensation and of
thought. For according to the views of those who posit the existence
of Ideas, those Ideas are at rest and are objects of thought; while if
they exist in us, it is impossible that they should be unmoved: for
when we move, it follows necessarily that all that is in us moves with
us as well. Clearly also they are objects of sensation, if they
exist in us: for it is through the sensation of sight that we
recognize the Form present in each individual.
  Again, if there be posited an accident which has a contrary, look
and see if that which admits of the accident will admit of its
contrary as well: for the same thing admits of contraries. Thus (e.g.)
if he has asserted that hatred follows anger, hatred would in that
case be in the 'spirited faculty': for that is where anger is. You
should therefore look and see if its contrary, to wit, friendship,
be also in the 'spirited faculty': for if not-if friendship is in
the faculty of desire-then hatred could not follow anger. Likewise
also if he has asserted that the faculty of desire is ignorant. For if
it were capable of ignorance, it would be capable of knowledge as
well: and this is not generally held-I mean that the faculty of desire
is capable of knowledge. For purposes, then, of overthrowing a view,
as has been said, this rule should be observed: but for purposes of
establishing one, though the rule will not help you to assert that the
accident actually belongs, it will help you to assert that it may
possibly belong. For having shown that the thing in question will
not admit of the contrary of the accident asserted, we shall have
shown that the accident neither belongs nor can possibly belong; while
on the other hand, if we show that the contrary belongs, or that the
thing is capable of the contrary, we shall not indeed as yet have
shown that the accident asserted does belong as well; our proof will
merely have gone to this point, that it is possible for it to belong.

                                 8

  Seeing that the modes of opposition are four in number, you should
look for arguments among the contradictories of your terms, converting
the order of their sequence, both when demolishing and when
establishing a view, and you should secure them by means of
induction-such arguments (e.g.) as that man be an animal, what is
not an animal is not a man': and likewise also in other instances of
contradictories. For in those cases the sequence is converse: for
'animal' follows upon 'man but 'not-animal' does not follow upon
'not-man', but conversely 'not-man' upon 'not-animal'. In all cases,
therefore, a postulate of this sort should be made, (e.g.) that 'If
the honourable is pleasant, what is not pleasant is not honourable,
while if the latter be untrue, so is the former'. Likewise, also,
'If what is not pleasant be not honourable, then what is honourable is
pleasant'. Clearly, then, the conversion of the sequence formed by
contradiction of the terms of the thesis is a method convertible for
both purposes.
  Then look also at the case of the contraries of S and P in the
thesis, and see if the contrary of the one follows upon the contrary
of the other, either directly or conversely, both when you are
demolishing and when you are establishing a view: secure arguments
of this kind as well by means of induction, so far as may be required.
Now the sequence is direct in a case such as that of courage and
cowardice: for upon the one of them virtue follows, and vice upon
the other; and upon the one it follows that it is desirable, while
upon the other it follows that it is objectionable. The sequence,
therefore, in the latter case also is direct; for the desirable is the
contrary of the objectionable. Likewise also in other cases. The
sequence is, on the other hand, converse in such a case as this:
Health follows upon vigour, but disease does not follow upon debility;
rather debility follows upon disease. In this case, then, clearly
the sequence is converse. Converse sequence is, however, rare in the
case of contraries; usually the sequence is direct. If, therefore, the
contrary of the one term does not follow upon the contrary of the
other either directly or conversely, clearly neither does the one term
follow upon the other in the statement made: whereas if the one
followed the other in the case of the contraries, it must of necessity
do so as well in the original statement.
  You should look also into cases of the privation or presence of a
state in like manner to the case of contraries. Only, in the case of
such privations the converse sequence does not occur: the sequence
is always bound to be direct: e.g. as sensation follows sight, while
absence of sensation follows blindness. For the opposition of
sensation to absence of sensation is an opposition of the presence
to the privation of a state: for the one of them is a state, and the
other the privation of it.
  The case of relative terms should also be studied in like manner
to that of a state and its privation: for the sequence of these as
well is direct; e.g. if 3/1 is a multiple, then 1/3 is a fraction: for
3/1 is relative to 1/3, and so is a multiple to a fraction. Again,
if knowledge be a conceiving, then also the object of knowledge is
an object of conception; and if sight be a sensation, then also the
object of sight is an object of sensation. An objection may be made
that there is no necessity for the sequence to take place, in the case
of relative terms, in the way described: for the object of sensation
is an object of knowledge, whereas sensation is not knowledge. The
objection is, however, not generally received as really true; for many
people deny that there is knowledge of objects of sensation. Moreover,
the principle stated is just as useful for the contrary purpose,
e.g. to show that the object of sensation is not an object of
knowledge, on the ground that neither is sensation knowledge.

                                 9

  Again look at the case of the co-ordinates and inflected forms of
the terms in the thesis, both in demolishing and in establishing it.
By co-ordinates' are meant terms such as the following: 'Just deeds'
and the 'just man' are coordinates of 'justice', and 'courageous
deeds' and the 'courageous man' are co-ordinates of courage.
Likewise also things that tend to produce and to preserve anything are
called co-ordinates of that which they tend to produce and to
preserve, as e.g. 'healthy habits' are co-ordinates of 'health' and
a 'vigorous constitutional' of a 'vigorous constitution' and so
forth also in other cases. 'Co-ordinate', then, usually describes
cases such as these, whereas 'inflected forms' are such as the
following: 'justly', 'courageously', 'healthily', and such as are
formed in this way. It is usually held that words when used in their
inflected forms as well are co-ordinates, as (e.g.) 'justly' in
relation to justice, and 'courageously' to courage; and then
'co-ordinate' describes all the members of the same kindred series,
e.g. 'justice', 'just', of a man or an act, 'justly'. Clearly, then,
when any one member, whatever its kind, of the same kindred series
is shown to be good or praiseworthy, then all the rest as well come to
be shown to be so: e.g. if 'justice' be something praiseworthy, then
so will 'just', of a man or thing, and 'justly' connote something
praiseworthy. Then 'justly' will be rendered also 'praiseworthily',
derived will by the same inflexion from 'the praiseworthy' whereby
'justly' is derived from 'justice'.
  Look not only in the case of the subject mentioned, but also in
the case of its contrary, for the contrary predicate: e.g. argue
that good is not necessarily pleasant; for neither is evil painful: or
that, if the latter be the case, so is the former. Also, if justice be
knowledge, then injustice is ignorance: and if 'justly' means
'knowingly' and 'skilfully', then 'unjustly' means 'ignorantly' and
'unskilfully': whereas if the latter be not true, neither is the
former, as in the instance given just now: for 'unjustly' is more
likely to seem equivalent to 'skilfully' than to 'unskilfully'. This
commonplace rule has been stated before in dealing with the sequence
of contraries; for all we are claiming now is that the contrary of P
shall follow the contrary of S.
  Moreover, look at the modes of generation and destruction of a
thing, and at the things which tend to produce or to destroy it,
both in demolishing and in establishing a view. For those things whose
modes of generation rank among good things, are themselves also
good; and if they themselves be good, so also are their modes of
generation. If, on the other hand, their modes of generation be
evil, then they themselves also are evil. In regard to modes of
destruction the converse is true: for if the modes of destruction rank
as good things, then they themselves rank as evil things; whereas if
the modes of destruction count as evil, they themselves count as good.
The same argument applies also to things tending to produce and
destroy: for things whose productive causes are good, themselves
also rank as good; whereas if causes destructive of them are good,
they themselves rank as evil.

                                10

  Again, look at things which are like the subject in question, and
see if they are in like case; e.g. if one branch of knowledge has more
than one object, so also will one opinion; and if to possess sight
be to see, then also to possess hearing will be to hear. Likewise also
in the case of other things, both those which are and those which
are generally held to be like. The rule in question is useful for both
purposes; for if it be as stated in the case of some one like thing,
it is so with the other like things as well, whereas if it be not so
in the case of some one of them, neither is it so in the case of the
others. Look and see also whether the cases are alike as regards a
single thing and a number of things: for sometimes there is a
discrepancy. Thus, if to 'know' a thing be to 'think of' it, then also
to 'know many things' is to 'be thinking of many things'; whereas this
is not true; for it is possible to know many things but not to be
thinking of them. If, then, the latter proposition be not true,
neither was the former that dealt with a single thing, viz. that to
'know' a thing is to 'think of' it.
  Moreover, argue from greater and less degrees. In regard to
greater degrees there are four commonplace rules. One is: See
whether a greater degree of the predicate follows a greater degree
of the subject: e.g. if pleasure be good, see whether also a greater
pleasure be a greater good: and if to do a wrong be evil, see
whether also to do a greater wrong is a greater evil. Now this rule is
of use for both purposes: for if an increase of the accident follows
an increase of the subject, as we have said, clearly the accident
belongs; while if it does not follow, the accident does not belong.
You should establish this by induction. Another rule is: If one
predicate be attributed to two subjects; then supposing it does not
belong to the subject to which it is the more likely to belong,
neither does it belong where it is less likely to belong; while if
it does belong where it is less likely to belong, then it belongs as
well where it is more likely. Again: If two predicates be attributed
to one subject, then if the one which is more generally thought to
belong does not belong, neither does the one that is less generally
thought to belong; or, if the one that is less generally thought to
belong does belong, so also does the other. Moreover: If two
predicates be attributed to two subjects, then if the one which is
more usually thought to belong to the one subject does not belong,
neither does the remaining predicate belong to the remaining
subject; or, if the one which is less usually thought to belong to the
one subject does belong, so too does the remaining predicate to the
remaining subject.
  Moreover, you can argue from the fact that an attribute belongs,
or is generally supposed to belong, in a like degree, in three ways,
viz. those described in the last three rules given in regard to a
greater degree.' For supposing that one predicate belongs, or is
supposed to belong, to two subjects in a like degree, then if it
does not belong to the one, neither does it belong to the other; while
if it belongs to the one, it belongs to the remaining one as well. Or,
supposing two predicates to belong in a like degree to the same
subject, then, if the one does not belong, neither does the
remaining one; while if the one does belong, the remaining one belongs
as well. The case is the same also if two predicates belong in a
like degree to two subjects; for if the one predicate does not
belong to the one subject, neither does the remaining predicate belong
to the remaining subject, while if the one predicate does belong to
the one subject, the remaining predicate belongs to the remaining
subject as well.

                                11

  You can argue, then, from greater or less or like degrees of truth
in the aforesaid number of ways. Moreover, you should argue from the
addition of one thing to another. If the addition of one thing to
another makes that other good or white, whereas formerly it was not
white or good, then the thing added will be white or good-it will
possess the character it imparts to the whole as well. Moreover, if an
addition of something to a given object intensifies the character
which it had as given, then the thing added will itself as well be
of that character. Likewise, also, in the case of other attributes.
The rule is not applicable in all cases, but only in those in which
the excess described as an 'increased intensity' is found to take
place. The above rule is, however, not convertible for overthrowing
a view. For if the thing added does not make the other good, it is not
thereby made clear whether in itself it may not be good: for the
addition of good to evil does not necessarily make the whole good, any
more than the addition of white to black makes the whole white.
  Again, any predicate of which we can speak of greater or less
degrees belongs also absolutely: for greater or less degrees of good
or of white will not be attributed to what is not good or white: for a
bad thing will never be said to have a greater or less degree of
goodness than another, but always of badness. This rule is not
convertible, either, for the purpose of overthrowing a predication:
for several predicates of which we cannot speak of a greater degree
belong absolutely: for the term 'man' is not attributed in greater and
less degrees, but a man is a man for all that.
  You should examine in the same way predicates attributed in a
given respect, and at a given time and place: for if the predicate
be possible in some respect, it is possible also absolutely. Likewise,
also, is what is predicated at a given time or place: for what is
absolutely impossible is not possible either in any respect or at
any place or time. An objection may be raised that in a given
respect people may be good by nature, e.g. they may be generous or
temperately inclined, while absolutely they are not good by nature,
because no one is prudent by nature. Likewise, also, it is possible
for a destructible thing to escape destruction at a given time,
whereas it is not possible for it to escape absolutely. In the same
way also it is a good thing at certain places to follow see and such a
diet, e.g. in infected areas, though it is not a good thing
absolutely. Moreover, in certain places it is possible to live
singly and alone, but absolutely it is not possible to exist singly
and alone. In the same way also it is in certain places honourable
to sacrifice one's father, e.g. among the Triballi, whereas,
absolutely, it is not honourable. Or possibly this may indicate a
relativity not to places but to persons: for it is all the same
wherever they may be: for everywhere it will be held honourable
among the Triballi themselves, just because they are Triballi.
Again, at certain times it is a good thing to take medicines, e.g.
when one is ill, but it is not so absolutely. Or possibly this again
may indicate a relativity not to a certain time, but to a certain
state of health: for it is all the same whenever it occurs, if only
one be in that state. A thing is 'absolutely' so which without any
addition you are prepared to say is honourable or the contrary. Thus
(e.g.) you will deny that to sacrifice one's father is honourable:
it is honourable only to certain persons: it is not therefore
honourable absolutely. On the other hand, to honour the gods you
will declare to be honourable without adding anything, because that is
honourable absolutely. So that whatever without any addition is
generally accounted to be honourable or dishonourable or anything else
of that kind, will be said to be so 'absolutely'.

                              Book III
                                 1

  THE question which is the more desirable, or the better, of two or
more things, should be examined upon the following lines: only first
of all it must be clearly laid down that the inquiry we are making
concerns not things that are widely divergent and that exhibit great
differences from one another (for nobody raises any doubt whether
happiness or wealth is more desirable), but things that are nearly
related and about which we commonly discuss for which of the two we
ought rather to vote, because we do not see any advantage on either
side as compared with the other. Clearly, in such cases if we can show
a single advantage, or more than one, our judgement will record our
assent that whichever side happens to have the advantage is the more
desirable.
  First, then, that which is more lasting or secure is more
desirable than that which is less so: and so is that which is more
likely to be chosen by the prudent or by the good man or by the
right law, or by men who are good in any particular line, when they
make their choice as such, or by the experts in regard to any
particular class of things; i.e. either whatever most of them or
what all of them would choose; e.g. in medicine or in carpentry
those things are more desirable which most, or all, doctors would
choose; or, in general, whatever most men or all men or all things
would choose, e.g. the good: for everything aims at the good. You
should direct the argument you intend to employ to whatever purpose
you require. Of what is 'better' or 'more desirable' the absolute
standard is the verdict of the better science, though relatively to
a given individual the standard may be his own particular science.
  In the second place, that which is known as 'an x' is more desirable
than that which does not come within the genus 'x'-e.g. justice than a
just man; for the former falls within the genus 'good', whereas the
other does not, and the former is called 'a good', whereas the
latter is not: for nothing which does not happen to belong to the
genus in question is called by the generic name; e.g. a 'white man' is
not 'a colour'. Likewise also in other cases.
  Also, that which is desired for itself is more desirable than that
which is desired for something else; e.g. health is more desirable
than gymnastics: for the former is desired for itself, the latter
for something else. Also, that which is desirable in itself is more
desirable than what is desirable per accidens; e.g. justice in our
friends than justice in our enemies: for the former is desirable in
itself, the latter per accidens: for we desire that our enemies should
be just per accidens, in order that they may do us no harm. This
last principle is the same as the one that precedes it, with, however,
a different turn of expression. For we desire justice in our friends
for itself, even though it will make no difference to us, and even
though they be in India; whereas in our enemies we desire it for
something else, in order that they may do us no harm.
  Also, that which is in itself the cause of good is more desirable
than what is so per accidens, e.g. virtue than luck (for the former in
itself, and the latter per accidens, the cause of good things), and so
in other cases of the same kind. Likewise also in the case of the
contrary; for what is in itself the cause of evil is more
objectionable than what is so per accidens, e.g. vice and chance:
for the one is bad in itself, whereas chance is so per accidens.
  Also, what is good absolutely is more desirable than what is good
for a particular person, e.g. recovery of health than a surgical
operation; for the former is good absolutely, the latter only for a
particular person, viz. the man who needs an operation. So too what is
good by nature is more desirable than the good that is not so by
nature, e.g. justice than the just man; for the one is good by nature,
whereas in the other case the goodness is acquired. Also the attribute
is more desirable which belongs to the better and more honourable
subject, e.g. to a god rather than to a man, and to the soul rather
than to the body. So too the property of the better thing is better
than the property of the worse; e.g. the property of God than the
property of man: for whereas in respect of what is common in both of
them they do not differ at all from each other, in respect of their
properties the one surpasses the other. Also that is better which is
inherent in things better or prior or more honourable: thus (e.g.)
health is better than strength and beauty: for the former is
inherent in the moist and the dry, and the hot and the cold, in fact
in all the primary constituents of an animal, whereas the others are
inherent in what is secondary, strength being a feature of the
sinews and bones, while beauty is generally supposed to consist in a
certain symmetry of the limbs. Also the end is generally supposed to
be more desirable than the means, and of two means, that which lies
nearer the end. In general, too, a means directed towards the end of
life is more desirable than a means to anything else, e.g. that
which contributes to happiness than that which contributes to
prudence. Also the competent is more desirable than the incompetent.
Moreover, of two productive agents that one is more desirable whose
end is better; while between a productive agent and an end we can
decide by a proportional sum whenever the excess of the one end over
the other is greater than that of the latter over its own productive
means: e.g. supposing the excess of happiness over health to be
greater than that of health over what produces health, then what
produces happiness is better than health. For what produces
happiness exceeds what produces health just as much as happiness
exceeds health. But health exceeds what produces health by a smaller
amount; ergo, the excess of what produces happiness over what produces
health is greater than that of health over what produces health.
Clearly, therefore, what produces happiness is more desirable than
health: for it exceeds the same standard by a greater amount.
Moreover, what is in itself nobler and more precious and
praiseworthy is more desirable than what is less so, e.g. friendship
than wealth, and justice than strength. For the former belong in
themselves to the class of things precious and praiseworthy, while the
latter do so not in themselves but for something else: for no one
prizes wealth for itself but always for something else, whereas we
prize friendship for itself, even though nothing else is likely to
come to us from it.

                                 2

  Moreover, whenever two things are very much like one another, and we
cannot see any superiority in the one over the other of them, we
should look at them from the standpoint of their consequences. For the
one which is followed by the greater good is the more desirable: or,
if the consequences be evil, that is more desirable which is
followed by the less evil. For though both may be desirable, yet there
may possibly be some unpleasant consequence involved to turn the
scale. Our survey from the point of view of consequences lies in two
directions, for there are prior consequences and later consequences:
e.g. if a man learns, it follows that he was ignorant before and knows
afterwards. As a rule, the later consequence is the better to
consider. You should take, therefore, whichever of the consequences
suits your purpose.
  Moreover, a greater number of good things is more desirable than a
smaller, either absolutely or when the one is included in the other,
viz. the smaller number in the greater. An objection may be raised
suppose in some particular case the one is valued for the sake of
the other; for then the two together are not more desirable than the
one; e.g. recovery of health and health, than health alone, inasmuch
as we desire recovery of health for the sake of health. Also it is
quite possible for what is not good, together with what is, to be more
desirable than a greater number of good things, e.g. the combination
of happiness and something else which is not good may be more
desirable than the combination of justice and courage. Also, the
same things are more valuable if accompanied than if unaccompanied
by pleasure, and likewise when free from pain than when attended
with pain.
  Also, everything is more desirable at the season when it is of
greater consequence; e.g. freedom from pain in old age more than in
youth: for it is of greater consequence in old age. On the same
principle also, prudence is more desirable in old age; for no man
chooses the young to guide him, because he does not expect them to
be prudent. With courage, the converse is the case, for it is in youth
that the active exercise of courage is more imperatively required.
Likewise also with temperance; for the young are more troubled by
their passions than are their elders.
  Also, that is more desirable which is more useful at every season or
at most seasons, e.g. justice and temperance rather than courage:
for they are always useful, while courage is only useful at times.
Also, that one of two things which if all possess, we do not need
the other thing, is more desirable than that which all may possess and
still we want the other one as well. Take the case of justice and
courage; if everybody were just, there would be no use for courage,
whereas all might be courageous, and still justice would be of use.
  Moreover, judge by the destructions and losses and generations and
acquisitions and contraries of things: for things whose destruction is
more objectionable are themselves more desirable. Likewise also with
the losses and contraries of things; for a thing whose loss or whose
contrary is more objectionable is itself more desirable. With the
generations or acquisitions of things the opposite is the case: for
things whose acquisition or generation is more desirable are
themselves also desirable. Another commonplace rule is that what is
nearer to the good is better and more desirable, i.e. what more nearly
resembles the good: thus justice is better than a just man. Also, that
which is more like than another thing to something better than itself,
as e.g. some say that Ajax was a better man than Odysseus because he
was more like Achilles. An objection may be raised to this that it
is not true: for it is quite possible that Ajax did not resemble
Achilles more nearly than Odysseus in the points which made Achilles
the best of them, and that Odysseus was a good man, though unlike
Achilles. Look also to see whether the resemblance be that of a
caricature, like the resemblance of a monkey to a man, whereas a horse
bears none: for the monkey is not the more handsome creature,
despite its nearer resemblance to a man. Again, in the case of two
things, if one is more like the better thing while another is more
like the worse, then that is likely to be better which is more like
the better. This too, however, admits of an objection: for quite
possibly the one only slightly resembles the better, while the other
strongly resembles the worse, e.g. supposing the resemblance of Ajax
to Achilles to be slight, while that of Odysseus to Nestor is
strong. Also it may be that the one which is like the better type
shows a degrading likeness, whereas the one which is like the worse
type improves upon it: witness the likeness of a horse to a donkey,
and that of a monkey to a man.
  Another rule is that the more conspicuous good is more desirable
than the less conspicuous, and the more difficult than the easier: for
we appreciate better the possession of things that cannot be easily
acquired. Also the more personal possession is more desirable than the
more widely shared. Also, that which is more free from connexion
with evil: for what is not attended by any unpleasantness is more
desirable than what is so attended.
  Moreover, if A be without qualification better than B, then also the
best of the members of A is better than the best of the members of
B; e.g. if Man be better than Horse, then also the best man is
better than the best horse. Also, if the best in A be better than
the best in B, then also A is better than B without qualification;
e.g. if the best man be better than the best horse, then also Man is
better than Horse without qualification.
  Moreover, things which our friends can share are more desirable than
those they cannot. Also, things which we like rather to do to our
friend are more desirable than those we like to do to the man in the
street, e.g. just dealing and the doing of good rather than the
semblance of them: for we would rather really do good to our friends
than seem to do so, whereas towards the man in the street the converse
is the case.
  Also, superfluities are better than necessities, and are sometimes
more desirable as well: for the good life is better than mere life,
and good life is a superfluity, whereas mere life itself is a
necessity. Sometimes, though, what is better is not also more
desirable: for there is no necessity that because it is better it
should also be more desirable: at least to be a philosopher is
better than to make money, but it is not more desirable for a man
who lacks the necessities of life. The expression 'superfluity'
applies whenever a man possesses the necessities of life and sets to
work to secure as well other noble acquisitions. Roughly speaking,
perhaps, necessities are more desirable, while superfluities are
better.
  Also, what cannot be got from another is more desirable than what
can be got from another as well, as (e.g.) is the case of justice
compared with courage. Also, A is more desirable if A is desirable
without B, but not B without A: power (e.g.) is not desirable
without prudence, but prudence is desirable without power. Also, if of
two things we repudiate the one in order to be thought to possess
the other, then that one is more desirable which we wish to be thought
to possess; thus (e.g.) we repudiate the love of hard work in order
that people may think us geniuses.
  Moreover, that is more desirable in whose absence it is less
blameworthy for people to be vexed; and that is more desirable in
whose absence it is more blameworthy for a man not to be vexed.

                                 3

  Moreover, of things that belong to the same species one which
possesses the peculiar virtue of the species is more desirable than
one which does not. If both possess it, then the one which possesses
it in a greater degree is more desirable.
  Moreover, if one thing makes good whatever it touches, while another
does not, the former is more desirable, just as also what makes things
warm is warmer than what does not. If both do so, then that one is
more desirable which does so in a greater degree, or if it render good
the better and more important object-if (e.g.), the one makes good the
soul, and the other the body.
  Moreover, judge things by their inflexions and uses and actions
and works, and judge these by them: for they go with each other:
e.g. if 'justly' means something more desirable than 'courageously',
then also justice means something more desirable than courage; and
if justice be more desirable than courage, then also 'justly' means
something more desirable than 'courageously'. Similarly also in the
other cases.
  Moreover, if one thing exceeds while the other falls short of the
same standard of good, the one which exceeds is the more desirable; or
if the one exceeds an even higher standard. Nay more, if there be
two things both preferable to something, the one which is more
highly preferable to it is more desirable than the less highly
preferable. Moreover, when the excess of a thing is more desirable
than the excess of something else, that thing is itself also more
desirable than the other, as (e.g.) friendship than money: for an
excess of friendship is more desirable than an excess of money. So
also that of which a man would rather that it were his by his own
doing is more desirable than what he would rather get by another's
doing, e.g. friends than money. Moreover, judge by means of an
addition, and see if the addition of A to the same thing as B makes
the whole more desirable than does the addition of B. You must,
however, beware of adducing a case in which the common term uses, or
in some other way helps the case of, one of the things added to it,
but not the other, as (e.g.) if you took a saw and a sickle in
combination with the art of carpentry: for in the combination the
saw is a more desirable thing, but it is not a more desirable thing
without qualification. Again, a thing is more desirable if, when added
to a lesser good, it makes the whole greater good. Likewise, also, you
should judge by means of subtraction: for the thing upon whose
subtraction the remainder is a lesser good may be taken to be a
greater good, whichever it be whose subtraction makes the remainder
a lesser good.
  Also, if one thing be desirable for itself, and the other for the
look of it, the former is more desirable, as (e.g.) health than
beauty. A thing is defined as being desired for the look of it if,
supposing no one knew of it, you would not care to have it. Also, it
is more desirable both for itself and for the look of it, while the
other thing is desirable on the one ground alone. Also, whichever is
the more precious for itself, is also better and more desirable. A
thing may be taken to be more precious in itself which we choose
rather for itself, without anything else being likely to come of it.
  Moreover, you should distinguish in how many senses 'desirable' is
used, and with a view to what ends, e.g. expediency or honour or
pleasure. For what is useful for all or most of them may be taken to
be more desirable than what is not useful in like manner. If the
same characters belong to both things you should look and see which
possesses them more markedly, i.e. which of the two is the more
pleasant or more honourable or more expedient. Again, that is more
desirable which serves the better purpose, e.g. that which serves to
promote virtue more than that which serves to promote pleasure.
Likewise also in the case of objectionable things; for that is more
objectionable which stands more in the way of what is desirable,
e.g. disease more than ugliness: for disease is a greater hindrance
both to pleasure and to being good.
  Moreover, argue by showing that the thing in question is in like
measure objectionable and desirable: for a thing of such a character
that a man might well desire and object to it alike is less
desirable than the other which is desirable only.

                                 4

  Comparisons of things together should therefore be conducted in
the manner prescribed. The same commonplace rules are useful also
for showing that anything is simply desirable or objectionable: for we
have only to subtract the excess of one thing over another. For if
what is more precious be more desirable, then also what is precious is
desirable; and if what is more useful be more desirable, then also
what is useful is desirable. Likewise, also, in the case of other
things which admit of comparisons of that kind. For in some cases in
the very course of comparing the things together we at once assert
also that each of them, or the one of them, is desirable, e.g.
whenever we call the one good 'by nature' and the other 'not by
nature': for dearly what is good by nature is desirable.

                                 5

  The commonplace rules relating to comparative degrees and amounts
ought to be taken in the most general possible form: for when so taken
they are likely to be useful in a larger number of instances. It is
possible to render some of the actual rules given above more universal
by a slight alteration of the expression, e.g. that what by nature
exhibits such and such a quality exhibits that quality in a greater
degree than what exhibits it not by nature. Also, if one thing does,
and another does not, impart such and such a quality to that which
possesses it, or to which it belongs, then whichever does impart it is
of that quality in greater degree than the one which does not impart
it; and if both impart it, then that one exhibits it in a greater
degree which imparts it in a greater degree.
  Moreover, if in any character one thing exceeds and another falls
short of the same standard; also, if the one exceeds something which
exceeds a given standard, while the other does not reach that
standard, then clearly the first-named thing exhibits that character
in a greater degree. Moreover, you should judge by means of
addition, and see if A when added to the same thing as B imparts to
the whole such and such a character in a more marked degree than B, or
if, when added to a thing which exhibits that character in a less
degree, it imparts that character to the whole in a greater degree.
Likewise, also, you may judge by means of subtraction: for a thing
upon whose subtraction the remainder exhibits such and such a
character in a less degree, itself exhibits that character in a
greater degree. Also, things exhibit such and such a character in a
greater degree if more free from admixture with their contraries; e.g.
that is whiter which is more free from admixture with black. Moreover,
apart from the rules given above, that has such and such a character
in greater degree which admits in a greater degree of the definition
proper to the given character; e.g. if the definition of 'white' be 'a
colour which pierces the vision', then that is whiter which is in a
greater degree a colour that pierces the vision.

                                 6

  If the question be put in a particular and not in a universal
form, in the first place the universal constructive or destructive
commonplace rules that have been given may all be brought into use.
For in demolishing or establishing a thing universally we also show it
in particular: for if it be true of all, it is true also of some,
and if untrue of all, it is untrue of some. Especially handy and of
general application are the commonplace rules that are drawn from
the opposites and co-ordinates and inflexions of a thing: for public
opinion grants alike the claim that if all pleasure be good, then also
all pain is evil, and the claim that if some pleasure be good, then
also some pain is evil. Moreover, if some form of sensation be not a
capacity, then also some form of failure of sensation is not a failure
of capacity. Also, if the object of conception is in some cases an
object of knowledge, then also some form of conceiving is knowledge.
Again, if what is unjust be in some cases good, then also what is just
is in some cases evil; and if what happens justly is in some cases
evil, then also what happens unjustly is in some cases good. Also,
if what is pleasant is in some cases objectionable, then pleasure is
in some cases an objectionable thing. On the same principle, also,
if what is pleasant is in some cases beneficial, then pleasure is in
some cases a beneficial thing. The case is the same also as regards
the things that destroy, and the processes of generation and
destruction. For if anything that destroys pleasure or knowledge be in
some cases good, then we may take it that pleasure or knowledge is
in some cases an evil thing. Likewise, also, if the destruction of
knowledge be in some cases a good thing or its production an evil
thing, then knowledge will be in some cases an evil thing; e.g. if for
a man to forget his disgraceful conduct be a good thing, and to
remember it be an evil thing, then the knowledge of his disgraceful
conduct may be taken to be an evil thing. The same holds also in other
cases: in all such cases the premiss and the conclusion are equally
likely to be accepted.
  Moreover you should judge by means of greater or smaller or like
degrees: for if some member of another genus exhibit such and such a
character in a more marked degree than your object, while no member of
that genus exhibits that character at all, then you may take it that
neither does the object in question exhibit it; e.g. if some form of
knowledge be good in a greater degree than pleasure, while no form
of knowledge is good, then you may take it that pleasure is not good
either. Also, you should judge by a smaller or like degree in the same
way: for so you will find it possible both to demolish and to
establish a view, except that whereas both are possible by means of
like degrees, by means of a smaller degree it is possible only to
establish, not to overthrow. For if a certain form of capacity be good
in a like degree to knowledge, and a certain form of capacity be good,
then so also is knowledge; while if no form of capacity be good,
then neither is knowledge. If, too, a certain form of capacity be good
in a less degree than knowledge, and a certain form of capacity be
good, then so also is knowledge; but if no form of capacity be good,
there is no necessity that no form of knowledge either should be good.
Clearly, then, it is only possible to establish a view by means of a
less degree.
  Not only by means of another genus can you overthrow a view, but
also by means of the same, if you take the most marked instance of the
character in question; e.g. if it be maintained that some form of
knowledge is good, then, suppose it to be shown that prudence is not
good, neither will any other kind be good, seeing that not even the
kind upon which there is most general agreement is so. Moreover, you
should go to work by means of an hypothesis; you should claim that the
attribute, if it belongs or does not belong in one case, does so in
a like degree in all, e.g. that if the soul of man be immortal, so are
other souls as well, while if this one be not so, neither are the
others. If, then, it be maintained that in some instance the attribute
belongs, you must show that in some instance it does not belong: for
then it will follow, by reason of the hypothesis, that it does not
belong to any instance at all. If, on the other hand, it be maintained
that it does not belong in some instance, you must show that it does
belong in some instance, for in this way it will follow that it
belongs to all instances. It is clear that the maker of the hypothesis
universalizes the question, whereas it was stated in a particular
form: for he claims that the maker of a particular admission should
make a universal admission, inasmuch as he claims that if the
attribute belongs in one instance, it belongs also in all instances
alike.
  If the problem be indefinite, it is possible to overthrow a
statement in only one way; e.g. if a man has asserted that pleasure is
good or is not good, without any further definition. For if he meant
that a particular pleasure is good, you must show universally that
no pleasure is good, if the proposition in question is to be
demolished. And likewise, also, if he meant that some particular
pleasure is not good you must show universally that all pleasure is
good: it is impossible to demolish it in any other way. For if we show
that some particular pleasure is not good or is good, the
proposition in question is not yet demolished. It is clear, then, that
it is possible to demolish an indefinite statement in one way only,
whereas it can be established in two ways: for whether we show
universally that all pleasure is good, or whether we show that a
particular pleasure is good, the proposition in question will have
been proved. Likewise, also, supposing we are required to argue that
some particular pleasure is not good, if we show that no pleasure is
good or that a particular pleasure is not good, we shall have produced
an argument in both ways, both universally and in particular, to
show that some particular pleasure is not good. If, on the other hand,
the statement made be definite, it will be possible to demolish it
in two ways; e.g. if it be maintained that it is an attribute of
some particular pleasure to be good, while of some it is not: for
whether it be shown that all pleasure, or that no pleasure, is good,
the proposition in question will have been demolished. If, however, he
has stated that only one single pleasure is good, it is possible to
demolish it in three ways: for by showing that all pleasure, or that
no pleasure, or that more than one pleasure, is good, we shall have
demolished the statement in question. If the statement be made still
more definite, e.g. that prudence alone of the virtues is knowledge,
there are four ways of demolishing it: for if it be shown that all
virtue is knowledge, or that no virtue is so, or that some other
virtue (e.g. justice) is so, or that prudence itself is not knowledge,
the proposition in question will have been demolished.
  It is useful also to take a look at individual instances, in cases
where some attribute has been said to belong or not to belong, as in
the case of universal questions. Moreover, you should take a glance
among genera, dividing them by their species until you come to those
that are not further divisible, as has been said before:' for
whether the attribute is found to belong in all cases or in none,
you should, after adducing several instances, claim that he should
either admit your point universally, or else bring an objection
showing in what case it does not hold. Moreover, in cases where it
is possible to make the accident definite either specifically or
numerically, you should look and see whether perhaps none of them
belongs, showing e.g. that time is not moved, nor yet a movement, by
enumerating how many species there are of movement: for if none of
these belong to time, clearly it does not move, nor yet is a movement.
Likewise, also, you can show that the soul is not a number, by
dividing all numbers into either odd or even: for then, if the soul be
neither odd nor even, clearly it is not a number.
    In regard then to Accident, you should set to work by means like
these, and in this manner.

                              Book IV
                                 1

  NEXT we must go on to examine questions relating to Genus and
Property. These are elements in the questions that relate to
definitions, but dialecticians seldom address their inquiries to these
by themselves. If, then, a genus be suggested for something that is,
first take a look at all objects which belong to the same genus as the
thing mentioned, and see whether the genus suggested is not predicated
of one of them, as happens in the case of an accident: e.g. if
'good' be laid down to be the genus of 'pleasure', see whether some
particular pleasure be not good: for, if so, clearly good' is not
the genus of pleasure: for the genus is predicated of all the
members of the same species. Secondly, see whether it be predicated
not in the category of essence, but as an accident, as 'white' is
predicated of 'snow', or 'self-moved' of the soul. For 'snow' is not a
kind of 'white', and therefore 'white' is not the genus of snow, nor
is the soul a kind of 'moving object': its motion is an accident of
it, as it often is of an animal to walk or to be walking. Moreover,
'moving' does not seem to indicate the essence, but rather a state
of doing or of having something done to it. Likewise, also, 'white':
for it indicates not the essence of snow, but a certain quality of it.
So that neither of them is predicated in the category of 'essence'.
  Especially you should take a look at the definition of Accident, and
see whether it fits the genus mentioned, as (e.g.) is also the case in
the instances just given. For it is possible for a thing to be and not
to be self-moved, and likewise, also, for it to be and not to be
white. So that neither of these attributes is the genus but an
accident, since we were saying that an accident is an attribute
which can belong to a thing and also not belong.
  Moreover, see whether the genus and the species be not found in
the same division, but the one be a substance while the other is a
quality, or the one be a relative while the other is a quality, as
(e.g.) 'slow' and 'swan' are each a substance, while 'white' is not
a substance but a quality, so that 'white' is not the genus either
of 'snow' or of 'swan'. Again, knowledge' is a relative, while
'good' and 'noble' are each a quality, so that good, or noble, is
not the genus of knowledge. For the genera of relatives ought
themselves also to be relatives, as is the case with 'double': for
multiple', which is the genus of 'double', is itself also a
relative. To speak generally, the genus ought to fall under the same
division as the species: for if the species be a substance, so too
should be the genus, and if the species be a quality, so too the genus
should be a quality; e.g. if white be a quality, so too should
colour be. Likewise, also, in other cases.
  Again, see whether it be necessary or possible for the genus to
partake of the object which has been placed in the genus. 'To partake'
is defined as 'to admit the definition of that which is partaken.
Clearly, therefore, the species partake of the genera, but not the
genera of the species: for the species admits the definition of the
genus, whereas the genus does not admit that of the species. You
must look, therefore, and see whether the genus rendered partakes or
can possibly partake of the species, e.g. if any one were to render
anything as genus of 'being' or of 'unity': for then the result will
be that the genus partakes of the species: for of everything that
is, 'being' and 'unity' are predicated, and therefore their definition
as well.
  Moreover, see if there be anything of which the species rendered
is true, while the genus is not so, e.g. supposing 'being' or
'object of knowledge' were stated to be the genus of 'object of
opinion'. For 'object of opinion' will be a predicate of what does not
exist; for many things which do not exist are objects of opinion;
whereas that 'being' or 'object of knowledge' is not predicated of
what does not exist is clear. So that neither 'being' nor 'object of
knowledge' is the genus of 'object of opinion': for of the objects
of which the species is predicated, the genus ought to be predicated
as well.
  Again, see whether the object placed in the genus be quite unable to
partake of any of its species: for it is impossible that it should
partake of the genus if it do not partake of any of its species,
except it be one of the species reached by the first division: these
do partake of the genus alone. If, therefore, 'Motion' be stated as
the genus of pleasure, you should look and see if pleasure be
neither locomotion nor alteration, nor any of the rest of the given
modes of motion: for clearly you may then take it that it does not
partake of any of the species, and therefore not of the genus
either, since what partakes of the genus must necessarily partake of
one of the species as well: so that pleasure could not be a species of
Motion,