tion of C to A. Hence the premises--

No electors are sober;
No electors are independent--

however suggestive, do not formally justify us in inferring any
connection between sobriety and independence. Formally to draw a
conclusion, we must have affirmative grounds, such as in this case we
may obtain by obverting both premises:

All electors are not-sober;
All electors are not-independent:
.'. Some who are not-independent are not-sober.

But this conclusion is not in the given terms.

(6) (a) If one premise be negative, the conclusion must be negative: and
(b) to prove a negative conclusion, one premise must be negative.

(a) For we have seen that one premise must be affirmative, and that thus
one term must be partly (at least) identified with the Middle. If, then,
the other premise, being negative, predicates the exclusion of the
remaining term from the Middle, this remaining term must be excluded
from the first term, so far as we know the first to be identical with
the Middle: and this exclusion will be expressed by a negative
conclusion. The analogy of the mediate comparison of quantities may here
again be noticed: if A is equal to B, and B is unequal to C, A is
unequal to C.

(b) If both premises be affirmative, the relations to the Middle of both
the other terms are more or less inclusive, and therefore furnish no
ground for an exclusive inference. This also follows from the function
of the middle term.

For the more convenient application of these canons to the testing of
syllogisms, it is usual to derive from them three Corollaries:

(i) Two particular premises yield no conclusion.

For if both premises be affirmative, _all_ their terms are
undistributed, the subjects by predesignation, the predicates by
position; and therefore the middle term must be undistributed, and there
can be no conclusion.

If one premise be negative, its predicate is distributed by position:
the other terms remaining undistributed. But, by Canon 6, the conclusion
(if any be possible) must be negative; and therefore its predicate, the
major term, will be distributed. In the premises, therefore, both the
middle and the major terms should be distributed, which is impossible:
e.g.,

Some M is not P;
Some S is M:
.'. Some S is not P.

Here, indeed, the major term is legitimately distributed (though the
negative premise might have been the minor); but M, the middle term, is
distribute