depends on the quantity of its Antecedent (which determines its
limitation), whilst its quality depends on the quality of its consequent
(which makes the predication), we may exhibit four forms:

A. _If A is B, C is D;_
I. _Sometimes when A is B, C is D;_
E. _If A is B, C is not D;_
O. _Sometimes when A is B, C is not D._

But I. and O. are rarely used.

As for Disjunctives, it is easy to distinguish the two quantities thus:

A. _Either A is B, or C is D;_
I. _Sometimes either A is B or C is D._

But I. is rarely used. The distinction of quality, however, cannot be
made: there are no true negative forms; for if we write--

_Neither is A B, nor C D,_

there is here no alternative predication, but only an Exponible
equivalent to _No A is B, and No C is D_. And if we write--

_Either A is not B, or C is not D,_

this is affirmative as to the alternation, and is for all methods of
treatment equivalent to A.

Logicians are divided in opinion as to the interpretation of the