Judgment and Proposition
Ideas are not enough to give us a comprehensive knowledge of things because the human intellect cannot grasp in one apprehensive act all the perfections of a thing.
The human mind has to proceed step by step, interrelating the ideas apprehended into judgment.
The logical union of different ideas in a judgment reflects the real unity of things.
Is a mental operation that pronounces the agreement or disagreement between two ideas.
As ideas are expressed in the concrete through the use of terms, judgment is expressed in the concrete through the use of proposition.
A proposition is a linguistic expression or the sensible sign of the judgment.
Constituents of a Proposition:
1. Subject – is the one spoken of, the one about whom or of which something is affirmed or denied.
2. Predicate – is what is affirmed or denied of the subject.
3. Copula – links the subject with the predicate.
4. The subject and predicate are called the matter because they are the materials or ingredients out of which the proposition is made.
5. The copula is the form for it is the unifying principle that gives the structure of a proposition.
Is that which gives a direct assertion of agreement or disagreement between the subject term and the predicate term.
The Standard-Form Categorical Proposition
A standard-form categorical proposition contains four elements:
1. The quantifier
2. The subject term
3. The predicate term
4. The copula
“All squatters are homeless.”
Subject : Squatters
The quantifier indicates the degree of universality (quantity) of the subject. A universal proposition is that which takes the subject in the entirety of its extension; a particular proposition limits this extension; and a singular proposition restricts it an individual subject.
The Universal Quantifier. A universal quantification makes use of all, every, any, and other words of similar import for affirmative propositions; and words such as no, none, and other words parallel to these for negative propositions.
“All books are reading materials.”
The Particular Quantifier. A particular quantification makes use of words such as some, at least one, most, almost all, the majority, and other words of similar import for particular propositions. These particular quantifiers claim that at least one member of the class denominated by the subject term is a member (or non-member) of the class denominated by the predicate term.
“Some students are scholars.”
It means that at least one student is a scholar.
The Copula. Is the linking verb is (am, are, was, were) and is not (am not, are not, was not, were not) indicating the agreement or disagreement between the subject term and the predicate term. The degree of agreement or disagreement is determined by the quantifier of the proposition.
Quality of the Categorical Proposition
The quality of a proposition is the relation established between two terms of the proposition. If there is an agreement between the two terms, then the proposition is affirmative; if there is disagreement, then the proposition is negative.
From the combination of quality and quantity, we derive four standard forms of categorical propositions. The vowels A, E, I, and O are used to represent each proposition. (AffIrmo – I affirm; nEgO – I negate)
The subject term of universal proposition is always universal.
The subject term of particular proposition is always particular.
Quantity of the Predicate Term
The predicate of an affirmative proposition is always particular.
The predicate of a negative proposition is always universal.
The Laws of Logical Opposition
Laws of Contrariety
1. Contraries cannot be both true.
(If one is true, the other is false)
2. Contraries may be both false.
(If one is false, the other is doubtful, i.e. either true or false)
Laws of Contradiction
1. Contradictories cannot be both true.
(If one is true, the other is false)
2. Contradictories cannot be both false.
(if one is false, the other is true)
Laws of Subcontrariety
1. Subcontraries cannot be both false.
(If one is false, the other is true)
2. Subcontraries may be both true.
(If one is true, the other is doubtful, i.e., either true or false)
Laws of Subalternation
1. What is true of the universal is true of the particular.
(If the universal is true, the particular is true)
2. (If the universal is false, the particular is doubtful)
3.What is denied of the particular is likewise denied of the universal.
(If the particular is false, the universal is false)
4. (If the particular is true, then the universal is doubtful)