Prior Analytics - Book I   

is syllogizing it is the assertion of that which is apparent and

generally admitted, as has been said in the Topics. The nature then of

a premiss and the difference between syllogistic, demonstrative, and

dialectical premisses, may be taken as sufficiently defined by us in

relation to our present need, but will be stated accurately in the

sequel.

I call that a term into which the premiss is resolved, i.e. both the

predicate and that of which it is predicated, 'being' being added

and 'not being' removed, or vice versa.

A syllogism is discourse in which, certain things being stated,

something other than what is stated follows of necessity from their

being so. I mean by the last phrase that they produce the consequence,

and by this, that no further term is required from without in order to

make the consequence necessary.

I call that a perfect syllogism which needs nothing other than

what has been stated to make plain what necessarily follows; a

syllogism is imperfect, if it needs either one or more propositions,

which are indeed the necessary consequences of the terms set down, but

have not been expressly stated as premisses.

That one term should be included in another as in a whole is the

same as for the other to be predicated of all of the first. And we say

that one term is predicated of all of another, whenever no instance of

the subject can be found of which the other term cannot be asserted:

'to be predicated of none' must be understood in the same way.



2



Every premiss states that something either is or must be or may be

the attribute of something else; of premisses of these three kinds

some are affirmative, others negative, in respect of each of the three

modes of attribution; again some affirmative and negative premisses

are universal, others particular, others indefinite. It is necessary