Various Works

  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 t
he 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

  shou
ld 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