CHAPTER VII.
IMMEDIATE INFERENCES Sec.1.Under the general title of Immediate Inference Logicians discuss three subjects, namely, Opposition, Conversion, and Obversion; to which some writers add other forms, such as Whole and Part in Connotation, Contraposition, Inversion, etc.

Of Opposition, again, all recognise four modes: Subalternation, Contradiction, Contrariety and Sub-contrariety.

The only peculiarities of the exposition upon which we are now entering are, that it follows the lead of the three Laws of Thought, taking first those modes of Immediate Inference in which Identity is most important, then those which plainly involve Contradiction and Excluded Middle; and that this method results in separating the modes of Opposition, connecting Subalternation with Conversion, and the other modes with Obversion.

To make up for this departure from usage, the four modes of Opposition will be brought together again in Sec.

9.
Sec.2.