Logical Argument: The Term and Kinds of Proposition

What really compose a Logical Argument?

In forming a logical argument, you need to really understand what compose it. Argument comprises propositions, which in turn contain terms.

Argument is the verbal expression of reasoning and is thus the main subject matter in studying correct reasoning. But arguments comprise statements (or propositions) which, in turn, necessarily contain terms. Hence, the formal study of correct thinking inevitably includes studying terms and propositions.

The Terms in a Logical Argument

Notice the significance of one’s knowledge about terms in the following arguments:

A ruler is 12 inches long.
The president is a ruler.
Therefore, the president is 12 inches long.

Man is spelled m-a-n.
Obama is a man.
Therefore, Obama is spelled m-a-n.

The invalidity of both arguments lies in the inconsistent use of terms. The term ‘ruler’ in the first argument is used equivocally and the term ‘man’ in the second is utilized in dissimilar suppositions. Clearly, to become good in reasoning, you have to be familiar with the various kinds and uses of terms.

(If you want more information about the various kinds and uses of terms in Logic, you may consult the online lecture “The Term in Logic” which is accessible through the search engine of www.ourHappySchool.com).

Judgment, Proposition, and Sentence

Judgment is made when we compare, contrast, or state relations between or among ideas. In this mental operation, the mind expresses the ideas’ agreement or disagreement.

Making a judgment is practically mentally affirming or denying one idea of another. For instance, our intellect may associate the ideas ‘this policy’ and ‘detrimental to the society’ to pronounce, “This policy is detrimental to the society.” This is a case of a judgment uttered in a ‘proposition’.

Thus, proposition is the verbal (oral or written) statement of judgment. Usually used interchangeably with statement, proposition is a verbal expression stating truth or falsity. (Though some logicians maintain that ‘proposition’ and ‘statement’ are semantically unalike, in this article at least, we practically treat them as substitutable.)

Truth and falsity

Terms, in themselves, cannot be said to be true or false because the ideas (or concepts) they represent are mere raw materials of knowledge. Logically, we cannot say, for instance, that the term ‘cat’ is ‘true’ (not unless we inaccurately define ‘truth’ as, say, ‘existent’).

But when we express relation between or among ideas or terms—that is, when we make judgment or proposition—then we can speak of truth or falsity. For example, “A cat is a mammal” is a judgment expressing relation between ‘cat’ and ‘mammal,’ which, in this case, embodies a ‘true’ proposition.

Truthrefers to the conformity of a proposition to reality whereas falsity, the disagreement. If what is express in a proposition matches reality, the proposition is true; if not, it is false. For example, the statement, “Kobe Bryant is a basketball star” is true; while the proposition, “Albert Einstein is a professional singer”is false. Thus, the barometer of truth is the correspondence of the judgment to reality.

There are propositions, however, that are deemed true based on the confirmed truth or falsity of other statements. Their truth is warranted by the reasoning process called inference.

For instance, when we accept as true that “Bella is a dog,” we can also affirm that “Bella is an animal”. Also considered a path to truth, inference is concluding from the truth (or falsity) of one or more relevant propositions.

Proposition and sentence: What is involved in a logical argument?

As we have explained, ‘proposition’ is the expression of judgment. It is somewhat related to ‘sentence’ though the two are not one and the same.

One of the differences between the two is that ‘sentence’ is made up of ‘words’ whereas ‘proposition’ is composed of ‘concepts.’ When a judgment is expressed in a sentence, the proposition is not the sentence itself, but that which is expressed or affirmed.

A good way to look at it is to consider proposition as the message, content, or meaning expressed, and the sentence is simply the vehicle to express it. Hence, what can be said to be either true or false is not the sentence but the proposition. Technically thus, proposition, not the sentence, is the bearer of truth or falsehood.

It is the proposition, not the sentence, which can either be true or false. All propositions necessarily involve assertion whereas many kinds of sentence do not express judgment. That is, many kinds of sentence do not affirm or deny anything.

For instance, interrogative sentence asks questions,exclamatory sentence expresses happiness, surprise, and other feelings, optativesentence conveys yearnings, wishes, and desires, and imperativesentence dispenses commands, but obviously none of them openly utter that something is or is not. Likewise, sentences which take the structure of a greeting, proposal, prayer, and request cannot be said to be either true or false.

However, there is one kind of sentence that is closely related to ‘proposition’. Being in the form of a statement, the declarative sentence (e.g. “Philippines is in the far east”) asserts something and thus pretty much appears to be like a ‘proposition.’

Nevertheless, the two are still not identical, because proposition, technically speaking, pertains to the judgment conveyed in a declarative sentence. Proposition refers to the meaning or content of a declarative sentence which expresses something that is either true or false. Therefore, it is the proposition, not the sentence, which is involved in a logical argument. (Read: Basic types of proposition)

Read also: Basic types of proposition with examples

For one thing, this lecture on proposition teaches us, especially in delivering debate speeches and responding to interpolation or point of information, that there is an appropriate type of proposition for each kind of judgment we wish to express. In a way, this topic warns us from improperly phrasing or forming our propositions … continue reading

‘Foundationalism’ states that for a system, structure, or faculty to be functionally sound, it must have a stable foundation. Since Debate is essentially about correct reasoning, a person must have a strong background in correct reasoning, like what is provided in this essay, to be a good debater.

© 2013-present by Jensen DG. Mañebog/ MyInfoBasket.com

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Reasoning and Debate: A Handbook and a Textbook by Jensen DG. Mañebog