On Judgment, Proposition, and Sentence: A Lecture in Logic
© 2011 by Jensen dG. Mañebog
IN LOGIC, term represents idea or concept. Ideas are the raw materials of knowledge but they cannot be said to be true or false in themselves. Only after we compare or contrast two or more ideas, or express relations, or an agreement or disagreement between them that we can speak of truth or falsity. The mental operation involved here is called judgment.
Judgment is an act in which the mind pronounces the agreement or disagreement of ideas among themselves. It is an act in which the intellect affirms or denies one idea of another. For instance, our intellect may relate the ideas this dog and Dalmatian and affirm, This dog is a Dalmatian. This is an example of a judgment expressed in a proposition. The proposition therefore is the oral or written expression of the judgment. Often used interchangeably with statement, it as a verbal expression proclaiming a truth or falsity.
Truth and falsity
Truth, is the agreement of a judgment with reality, falsity, the disagreement.If a proposition coincides with reality, it is true and, if not, it is false. The truth of a proposition is verified by comparing it with the reality it is supposed to express. To state, The author of this lecture is a woman is false, while to propose, This lecture is about Logic is true. The "test" of truth is, therefore, agreement of the judgment with reality. We refer to this as objective evidence and thus our criterion of truth.
Nonetheless, there are statements that are considered true because other propositions verified as true serve as their bases. Such truths are affirmed by the logical process called inference. By inference, we mean proceeding from the truth-value of one or more propositions to the truth-value of another pertinent and consequential proposition. Thus, when we affirmed that Hachiko is a dog, we can infer that Hachiko is a mammal. (More of this will be discussed under the topic ‘Reasoning and Inference’). In this sense, inference can also be considered a pathway to truth.
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Proposition (Statement) and Sentences
Ideas are expressed in words which we call terms. In the same way, judgments are expressed in sentences we call propositions or statements.
Propositionsare distinct from sentences. For one thing, proposition, which is an expression of judgment, is made up of concepts while sentence is made up of words. In a declarative sentence, the proposition is not the sentence itself, but that which is expressed or asserted, which is either true or false. In other words, a sentence is not the bearer of truth or falsehood. These are properties of propositions.
Moreover, while all propositions necessarily contain assertion, not all sentences convey judgment. Some sentences do not assert or deny anything, hence can not be said to be either true or false. Interrogative sentences, for instance, are used to ask questions. Through imperative sentences, we issue commands. We express joy, surprise, or some other emotions through exclamatory sentences. Optative sentences express wishes or desires. These types of sentences, plus those which take the form of a request, proposal, prayer, greeting, etc. do not explicitly state that something is or is not. Clearly then, all statements are sentences but not all sentences are propositions.
There is only one kind of sentence that is of prime importance in Logic because it is through this form that judgments are plainly expressed. It is called declarative sentence (e.g. “Libya is a country”). Nonetheless, declarative sentence is still not synonymous with proposition because proposition, technically speaking, refers to the judgment expressed in a declarative sentence.
There are three basic types of propositions: categorical propositions which declare something about two terms; hypothetical propositions which express conditions; and modal propositions which state the mode in which a term agrees or disagrees with another term.
Jensen dG. Mañebog, the contributor, is a Debate and Philosophy professor in a university in Quezon City, Philippines.
How to cite this article:
Jensen dG. Mañebog. “Judgment, Proposition, and Sentence: A Lecture in Logic” @ www.OurHappySchool.com
1. Give an example for each kind of sentences mentioned in the lecture (in a yellow paper or Microsoft Word file (.doc.) to be submitted to your professor).
2. In not more than two (2) sentences, explain why this lecture is important.
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