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

AND THE ARISTOTELIAN SYLLOGISM. 149
(1) s, except when it is the last letter of the name, in
dicates that the proposition denoted by the
preceding vowel is to be converted simply (conversio
Simplex}.
(2) /, except when it is the last letter of the name, in
dicates that the proposition denoted by the
preceding vowel is to be converted Per accidens
(in Particularsm propositionnt).
(3) //i, indicates that the premises of the imperfect syl
logism are to be transposed, the major becoming
the minor, and vice versa (Metathesis sive Mu-
tatio prccmissarunt).
By these means we shall have changed the premises
of the imperfect syllogism into two equivalent but
new premises, from which a valid conclusion may
be drawn in fig.
i. The initial letter B, C, D, or F,
of the name of
mood in i.
fig. in
the imperfect syllogism, shows the
which the new premises give a valid
conclusion. If there is an s or / at the end of the
name of the imperfect syllogism, it means that the new
syllogism in fig.
i. does not give a conclusion identical
with that of the imperfect syllogism, but one from
which the latter can be derived by conversion, simple
or per accidens.
(4) c, indicates that the mood must be reduced
Example :
by a distinct process called indirect reduction,
to be explained shortly. The process was
formerly called Conversio syllogismi,
or ductio
per Contradictoriam propositionem sive per im-
possibile. Hence it is an error to substitute a
k for this c, as Jevons and Fowler do.
Reduce
Camestres. This is in fig. ii. :
All P is M,
No S is M ;
/.No S is P.