Similarly, in the mediate comparison of quantities, if we are told that A and C are both of them unequal to B, we can infer nothing as to the relation 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.