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

98 IMPORT OF PROPOSITIONS AND JUDGMENTS.
(4) Subject in intension, predicate in extension,
" The attributes signified by humanity indicate
the presence of an object belonging to the
class mortal beings"
The fourth interpretation is not of much importance.
In such a proposition as "Some glittering things are
not golden," we have an instance which naturally falls
into this division, as it means that the attribute "glit
tering" does not always indicate the presence
of a
golden object. Similarly we may interpret
" No plants
with opposite leaves are orchids." But it is most
unnatural to force our ordinary propositions into this
form.
The first three interpretations are of great importance,
and we will examine them in turn.
2. The oldest view is the first, according to which
the proposition expresses the relation of subject and
attribute, or, in grammatical terms, of substantive and
adjective. The subject of the proposition is read prim
arily in extension, because it signifies what we call a
"
"
1
real thing or a group of such the ; predicate is read
in intension, because it signifies certain qualities which
are predicated of the thing. On this interpretation
of the proposition, only the subject can have the sign
of quantity,
"
"
all
or
"
some," for only the subject
refers to a "thing" or "things." Hence this gives
the fourfold division of propositions A, E, I, O. This
classification fits the diagrams so badly (see ch. III.
5) because they naturally require the predicate also
to be quantified.
This first interpretation of propositions is called the
predicative view. The second, which we have already
1 Notice that the subject also implies intension, because it must
signify certain qualities by which we identify the thing referred to.