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

146
MEDIATE INFERENCE
But in the fourth figure the conclusion unexpectedly
makes the statement about
f All roses are plants,
"
things needing air
"
\A11 plants need air ;
Some things needing air are roses.
This is the mood AAI in fig. iv., called Bramantip. It
is entirely superfluous, as well as unnatural, for the con
clusion, if desired, can be obtained by simple conversion
of the conclusion in Barbara. The same remark applies
to the moods AEE and IAI in fig. iv., called Camenes
and Dimaris respectively, in which the conclusion,
when we think naturally, is drawn in Celarent and Darii
respectively; and if the conclusion of the fourth figure
is required, it is obtained by conversion.
The two remaining moods of fig.
iv. EAO and EIO,
called Fesapo and Fresison respectively fall less readily into
the form of fig. i. If we convert the major of Fesapo simply,
and the minor per accidens, we have a pair of premises from
which the conclusion of Fesapo follows, in Ferio of fig. i. ;
also, from Fesapo we may derive Fresiso?t by taking the
"
"
subaltern of the minor premise.
10. We may thus sum up the reasons why the first
figure is, as Aristotle held, superior
(a) It alone complies directly
to the others :
with the Canon of
Reasoning ; hence its scientific value, as
illustrated above.
(b) It will prove each of the conclusions A, E, I, and
O, and is the only mood in which A can be
proved.
(c) In the principal mood of this figure, the relative
extension of the major, middle, and minor
terms corresponds to the relative order of their
names,