Categorical propositions are divided according to their quantity into Universal and Particular and according to their quality into Affirmative and Negative.
A universal proposition is one in which the predicate refers to the whole of the logical subject.
ILLUSTRATIONS:
(1) All men are mortal.
(2) All civilized men cook their food.
(3) No dogs are immortal.
(4) Every man was once a boy.
Considering the first proposition, “mortal,” the logical predicate, refers to the whole of the logical subject “men.” Similarly “cook their food” refers to the whole of the term “civilized men”; “immortal” to the whole of the term “dogs,” and “once a boy” to the whole of the term “man.”
In considering the definition of a universal proposition it is necessary to keep in mind the distinction between a logical and a grammatical subject, as in the second proposition the logical predicate, “cook their food,” refers to only a part of the grammatical subject, men, and, therefore, the proposition might fallaciously be termed a particular proposition rather than a universal.
A particular proposition is one in which the predicate refers to only a part of the logical subject.