Ordinary A—All of the subject belongs to a part of the predicate.
Co-extensive A—All of the subject belongs to all of the predicate.
E—None of the subject belongs to any part of the predicate.
I—Some of the subject belongs to some of the predicate.
O—Some of the subject is excluded from the whole of the predicate.
In general it may be said that the affirmative propositions are inclusive while the negatives are exclusive.
A term is said to be distributed when it is referred to as a definite whole.
“A” distributes the logical subject only, “E” both logical subject and logical predicate, “I” neither logical subject nor logical predicate, “O” the logical predicate only. The co-extensive “A” distributes both subject and predicate.
It is essential that the student know by heart the distribution of the terms of the logical propositions. Some keyword like uaesneop may be used as an aid to the memory. This means the universals A and E distribute their subjects, while the negatives E and O distribute their predicates.