Saepeo
10. SUMMARY.
(1) A logical proposition is a judgment expressed in words.
(2) The three kinds of logical propositions are categorical, hypothetical, disjunctive.
A categorical proposition is one in which the assertion is made unconditionally.
A hypothetical proposition is one in which the assertion depends upon a condition.
A disjunctive proposition is one which asserts an alternative.
The most common word-signs of the categorical proposition are “all,” “no,” “some” and “some-not,” of the hypothetical, “if” and of the disjunctive, “either-or.”
(3) Every logical categorical proposition has the four elements: quantity sign, subject, copula and predicate.
The quantity sign indicates the extension of the proposition; the logical subject is that of which something is affirmed or denied; the logical predicate is the term which is affirmed or denied of the subject; the copula is always some form of “to be” and is used to connect subject and predicate. “Not” is sometimes used with the copula.