Illustrations of the O proposition:
1. “Some men are not wise.”
2. “Some laws are not just.”
3. “Some novels are not helpful.”
The significance of the O proposition may be shown by two intersecting circles as in [Fig. 4]:
FIG. 4.
A similar diagram represents the I proposition, the only difference being in the part shaded. In the O proposition the investigated field is all of the “men” circle outside of the “wise” circle, while in the I proposition the known field is that part of the “men” circle inside the “wise” circle.
In comparing the four diagrams the student will note that the affirmative propositions are inclusive, while the negative propositions are exclusive.
(5) The Distribution of Subject and Predicate.