Definition of the Proposition
Just as the idea is expressed in the term, the judgment is expressed in the proposition. Its definition, three elements (subject, predicate, copula), logical form, and the properties of quality and quantity.
The Proposition is the verbal expression of a judgment. It has three elements: subject (the term of which something is predicated), predicate (the term predicated), and copula (the verb 'is' or 'is not' expressing the act of predication — never expressing mere existence or essential identity, only the logical relation of predication). The proposition has two properties: Quality (affirmative or negative, depending on whether the copula is positive or negative) and Quantity (universal, particular, singular, or indefinite, depending on the scope of the subject-term). The four basic types — Universal Affirmative (A), Universal Negative (E), Particular Affirmative (I), and Particular Negative (O) — and the Two Distribution Principles (the subject of universal propositions and the predicate of negative propositions are always distributed) are the fundamental tools of syllogistic analysis.
Just as the idea is expressed exteriorly by the term, so the judgment is expressed exteriorly by the Proposition.
A proposition is a judgment expressed in terms — a formula of terms which affirms or denies a predicate of a subject, such affirmation or denial being expressed by the copula.
Elements of the Proposition
Every proposition has three elements:
- Subject: a term expressing the idea of which another idea is affirmed or denied.
- Predicate: a term expressing the idea which is affirmed or denied of the subject.
- Copula: the present tense of the verb to be, by which the affirmation or denial is expressed.
The subject and predicate together constitute the material element of the proposition. The copula (which is the expression of the judgment proper) is the formal element.
Logical Form
The copula is always the present tense, indicative mood, of the verb to be. Propositions containing other verbs or other tenses may be reduced to logical form — restated in the subject-copula-predicate pattern:
| Original Form | Logical Form |
|---|---|
| John ran away | John is one-having-run-away |
| Mary will play | Mary is one-about-to-play |
| Charles has not arrived | Charles is not one-having-arrived |
| Patience brings blessings | Patience is a-thing-bringing-blessings |
| No man has been prejudged | All men are not those-prejudged |
Two things to notice: (1) the mode of reducing a proposition to logical form; (2) in negative propositions, the negation is essentially in the copula, even when the verb is positive and the negation is expressed in a particle prefixed to the subject (as in the last example).
When to be is used in the sense of to exist, as in “God is,” the reduction is: “God is one-existing.”
Quality and Quantity
Every proposition has the properties known as quality and quantity:
- The quality of a proposition is determined by the copula as affirmative or negative.
- The quantity of a proposition is determined by the Extension of its subject as universal or particular.
Thus “All men are mortal” is universal in quantity and affirmative in quality. “Some men are not wise” is particular in quantity and negative in quality.
Summary of the Article
This short Article has furnished the definition of the proposition, set forth its three elements (subject, predicate, copula) in detail, and classed these as formal (the copula) and material (subject and predicate). It has provided a sufficient account of what is meant by the quality and quantity of propositions.