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

136
MEDIATE INFERENCE
(4) The mood AO in i.
fig. would be :
All M is P,
Some S is not M,
from which there is no conclusion, for the same reason
as in (2)
it would lead to an Illicit Major.
(5) The mood EA in fig.
No M is P,
All S is M,
i. is :
from which the only valid conclusions about S are :
(a) No S is P,
(&) Some S is not P,
the second being the weakened conclusion.
(6) The mood El in fig.
i. is :
No M is P,
Some S is M,
from which the only valid conclusion about S is :
(7) The mood IA in fig.
Some S is not P.
Some M is P,
All S is M,
i. would be :
from which there is no conclusion, for the premises
involve an Undistributed Middle.
(8) The mood OA in fig.
i. would be :
Some M is not P,
All S is M,
from which there is no conclusion, because of the
Undistributed Middle.
We have thus found six moods in fig. i., giving valid
conclusions about S, of which two are
"
weakened
moods" (i.e., have weakened conclusions). We shall