ABSTRACT
This chapter discusses the relations between propositions having precisely the same subject and predicate, but differing in quality or in quantity. It considers the implications of the several types of categorical proposition beyond these limits. The principal types are known as the converse and the obverse; the other forms are obtained by combining, or repeating alternately, the steps by which the converse and the obverse are obtained. The student who has no special distaste for dealing with a few easy symbols will find no difficulty with the Educations. In the light of what has just been said about contradictory terms, it is also possible now to give alternative formulations to the Laws of Contradiction and Excluded Middle. It will be convenient to give these alternative formulations at this stage because they will be helpful in connection with the doctrine of Eductions.
