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

72
"
"
Europeans
and the diagram
OPPOSITION OF PROPOSITIONS.
coincides with the class
Fig. 5-
"
Frenchmen,
where part of S coincides with the whole of P.
We do not know from the form of the proposition
whether the predicate signifies the whole or only a part
of P. And further, since
"
"
some means
"
some at
least," we do not know from the form of the proposition
whether the whole or part of the Subject itself is referred
to. In the examples represented by figs. 4 and 5,
"
"
some
means only a part, and the propositions are
(a) part of S coincides with part of P,
(b) part of S coincides with all of P.
But as far as the mere form of the proposition goes,
the two following possibilities are not excluded :
(c) all of S coincides with part of P,
(d)
all of S coincides with all of P.
These are represented
On the other hand, the
i by figs,
student will
and
find
2
respectively.
that nearly all
propositions, which can be brought to the form I, will
be of the type (a) or (b).
The proposition tells us that some at least of the
class S fall outside the class P. Here, again, there are
two chief possibilities of meaning, although the distinction
does not depend on that of part and whole of P.
(a) P
may be a wider class than S, and S partly outside it,
partly within it : "Some metals are brittle," represented