亚里士多德解释编—-词语与诸命题的关系

This is an exhaustive enumeration of all the  pairs  of oppos ite propositions

that can possibly be framed. This last group should remain distinct from those

which preceded it, since it employs as its subject the express ion ’not-man’.

When  the  verb  ’is’  does not  fit  the structure  of  the sentence (for  instance,

when the verbs ’walks’, ’enjoys health’ are used), that s cheme applies, which

applied when the word ’is’ was added.

Thus  we  have  the  propositions:  ’every  man  enjoys  health’,  ’every  man

does -not-enjoy-health’, ’all that is not-man enjoys health’,  ’all that is  not-man

does -not-enjoy-health’. We must not in these propositions use the expression

’not  every  man’.  The  negative  must  be  attached  to  the  word  ’man’,  for  the

word ’every’  does not give to the subject a universal significance, but implies

that, as a subject, it is dis tributed. This is plain from  the following pairs: ’man

enjoys health’, ’man does not enjoy health’; ’not-man enjoys health’, ’not man

does   not  enjoy  health’.  These  propositions  differ  from  the  former  in  being

indefinite  and  not  universal in  character.  Thus  the  adjec tives  ’every’ and  no

additional s ignificance  except  that the  subject, whether  in  a  positive or  in  a

negative sentence, is  distributed. The rest of the  sentence,  therefore, will in

each case be the same.

Since the  contrary  of  the proposition  ’every  animal  is  just’ is  ’no  animal  is

just’, it is plain that these two propositions will never both be true at the same

time  or  with  reference  to  the  same  subject.  Sometimes,  however,  the

contradictories of these contraries will both be true, as in the instance before

us: the propositions ’not every animal is just’ and ’some animals  are just’ are

both true.

Further, the proposition ’no man is just’ follows from the proposition ’every

man  is  not just’  and the  proposition ’not  every man is not  just’,  which is  the

opposite  of  ’every  man  is   not-just’,  follows  from  the  proposition  ’some  men

are just’; for if this be true, there must be some just men.

It is evident, also, that when the subject is individual, if a question is asked

and the negative answer is the true one, a certain positive proposition is also

true.  Thus,  if  the  question  were  asked  Socrates  wise?’  and  the  negative

answer were the true one, the positive inference ’Then Socrates is unwise’ is

correct. But no such inference is correct in the case of universals, but rather a

negative proposition. For instance, if to the question ’Is every man wise?’ the

answer  is  ’no’,  the inference  ’Then  every  man  is  unwise’  is false.  But  under

these circumstances the inference ’Not every man is wise’ is correct. This last

is  the  contradictory,  the  former  the  contrary.  Negative  expressions,  which

consist of an indefinite noun or predic ate, such as ’not-man’ or ’not-just’, may

seem to  be  denials  containing  neither noun  nor verb in  the  proper s ense  of

the words. But they are not. For a denial must always  be either true or false,

and  he  that  uses  the  ex pression  ’not man’, if nothing more  be added, is  not

nearer but rather further from making a true or a false statement than he who

uses the expression ’man’.

The propositions ’everything that is not man is just’, and the contradictory of

this,  are  not  equivalent  to any  of the  other propositions;  on  the  other  hand,

the  proposition  ’ev erything  that  is  not  man  is  not  just’  is  equivalent  to  the

proposition ’nothing that is not man is just’.

The  conversion  of  the  position  of  subject  and  predicate  in  a  sentence

involves no difference in its meaning. Thus we say ’man is white’ and ’white is

man’.  If  these  were  not  equivalent,  there  would  be  more  than  one

contradictory  to  the  same  proposition,  whereas  it  has  been  demonstrated’

that  each proposition  has one  proper contradictory  and one only.  For of the

proposition ’man  is white’ the appropriate  contradictory is  ’man is  not white’,

and  of  the  proposition  ’white  is  man’,  if  its  meaning  be  different,  the

contradictory  will either  be  ’white is  not  not-man’  or ’white  is not  man’. Now

the former  of these is  the contradictory  of  the proposition ’white  is not-man’,

and  the  latter  of  these  is  the  contradictory  of  the proposition  ’man  is  white’;

thus there will be two contradictories to one proposition.

It is evident,  therefore, that the inversion  of the  relative position of  subject

and predicate does not affect the sense of affirmations and denials.