An introductory text-book of logic - Mellone, Sydney - Rare Books at ...

Il6 MEDIATE INFERENCE
merely a verbal change i.e., the same relation stated
in different words. We have another side or aspect of
the original fact stated. On the class -view of pro
positions, this is evident ; and it appears to be equally
true on any other interpretation. We begin with a
given relation between two classes or spheres,
"
S is P
Fig. 1 8. Fig. 19.
as "All
The diagrams make it visibly evident that the relation
of S and P here spoken of has several aspects, of which
the given proposition states only one viz., that all S is
included in P. Another aspect is, that some at least of
P is included in S (the converse) ; another, that no S is
outside of P (the obverse) ; another, that nothing out
side of P is in S (the contrapositive) ; another, that some
at least of what is outside S is outside P (the inverse).
Hence, in Immediate Inference, we have not the same
relation between S and P restated (a merely verbal
change); and we have not a new relation between S
and P stated
(a complete inference); but we have
another aspect of the original relation stated.
Immediate Inference is not a trivial matter. It is of
real practical importance.
In the interpretation of legal
documents, rules, &c., the real implications of the state
ments made will be much more evident if we remember
these elementary logical processes. In ordinary thought
we are constantly making mistakes through neglect of