_Of Deductive Inferences._
$ 442. Deductive inferences are of two kinds--Immediate and Mediate.
§ 443. An immediate inference is so called because it is effected
without the intervention of a middle term, which is required in
mediate inference.
§ 444. But the distinction between the two might be conveyed with at
least equal aptness in this way--
An immediate inference is the comparison of two propositions directly.
A mediate inference is the comparison of two propositions by means of
a third.
§ 445. In that sense of the term inference in which it is confined to
the consequent, it may be said that--
An immediate inference is one derived from a single proposition.
A mediate inference is one derived from two propositions conjointly.
§ 446. There are never more than two propositions in the antecedent of
a deductive inference. Wherever we have a conclusion following from
more than two propositions, there will be found to be more than one
inference.
§ 447. There are three simple forms of immediate inference, namely
Opposition, Conversion and Permutation.
§ 448. Besides these there are certain compound forms, in which
permutation is combined with conversion.