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.

11



There is no unity about an affirmation or denial which, either

positively or negatively, predicates one thing of many subjects, or

many things of the same subject, unless that which is indicated by the

many is really some one thing. do not apply this word 'one' to those

things which, though they have a single recognized name, yet do not

combine to form a unity. Thus, man may be an animal, and biped, and

domesticated, but these three predicates combine to form a unity. On

the other hand, the predicates 'white', 'man', and 'walking' do not

thus combine. Neither, therefore, if these three form the subject of

an affirmation, nor if they form its predicate, is there any unity

about that affirmation. In both cases the unity is linguistic, but not

real.

If therefore the dialectical question is a request for an answer,

i.e. either for the admission of a premiss or for the admission of one

of two contradictories-and the premiss is itself always one of two

contradictories-the answer to such a question as contains the above

predicates cannot be a single proposition. For as I have explained

in the Topics, question is not a single one, even if the answer