Sentence and Proposition
Sentence
Sentence= Proposition= Statement
• Sentence is the unit or part of some language.
• Sentences can be expressed in all tense (present, past or future)
• Sentence is not able to explain quantity and quality.
• A sentence may be interrogative, simple or declarative, command or
imperative, exclamatory, indicative, affirmative, negative, skeptical &
etc.
Note : Only indicative sentences are proposition.
All kind of sentences are not proposition, only those sentences are called
proposition while they will determine or evaluate in terms of truthfulness or
falsity.
Sentences are governed by its own grammar.
(For exp- sentence of Tamil language govern
by Tamil grammar)
Sentences are correct or incorrect / pure or impure.
Sentences are may be either true or false.
Proposition are regarded as the material of our reasoning and we also say that
proposition and statements are regarded as same.
1. Proposition is the unit of logic.
2. Proposition always comes in present tense. (sentences - all tenses)
3. Proposition can explain quantity and quality. (sentences- cannot)
4. Meaning of sentence is called proposition.
5. Sometime more than one sentences can expressed only one proposition.
Example:
It is raining.
The above sentences have only one meaning or one proposition.
Sometimes a sentence may express different propositions in different
contexts.
Example:
Present P.M. is Intelligent.
(In 1947 context- Pt. Nehru, In 2020 context- Mr. Narendra Modi)
Sentences are expressed through its own language. But Propositions are
Language neutral.
Proposition must be either True or False.
(Truth and Falsity can be apply only to proposition)
When a sentence both term like subject and predicate are regarded as
noun, then sentence is called proposition. We can say that all propositions are
sentences, but not all sentences are propositions.
There are three components in every proposition, which are known as term.
By term, we mean any word or word phrase, which is used in a proposition as
subject or predicate.
Subject term- It refers to the assertion or denying something.
Predicate term- It refers to the assertion or denying of what.
Copula- It is defined as negative or affirmative. It comes between subject and
predicate term.
E.g.- Ram is a good person.
(sub) (copula) (predicate)
Classification/ Types of Propositions
There are 3 types of propositions according to the relation of terms.
Categorical Proposition-There are no condition (Unconditional) for their
assertion.
Conditional or Hypothetical Proposition- It is also known as a type of
compound proposition. This proposition is false, when the antecedent is true
and the consequent is false.
Distinctive proposition- It is also known as a type of compound proposition. It
says that this proposition is true, if at least one of the component of proposition
are also true.
Categorical Proposition
It is regarded as a statement which talks about the relationship between
categories/ classes. It shows the complete, partial or complete separate
connection of one category with another category.
The Deductive argument formulated by the categorical propositions.
Categorical propositions are known as the fundamental elements, the building
blocks of argument, in the classical account of deductive logic.
Four kinds of Categorical Propositions
According to quantity and quality we can find four categorical propositions
1. Universal Affirmative – Type A Proposition
2. Universal Negative - Type E Proposition
3. Particular Affirmative - Type I Proposition
4. Particular Negative - Type O Proposition
Identification of Categorical Proposition
1. A – Proposition
Main Identity
• All
Other words to identify
• Each, every, any, always, certainly, absolutely, in all cases, necessarily
• If these words comes along with ‘Not’(e.g- not each…) then it will became O
proposition
Standard Form
• All S is P
• All politicians(S) are liars(P)
2. E – Proposition
Main Identity
• No
Other words to identify
• Never, none, in no case, not a single
Standard Form
• No S is P
• No politicians(S) are liars(P)
Identification of Categorical Proposition
3. I – Proposition
Main Identity
• Some
Other words to identify
• A few, the few, sometimes, almost all, generally, most, many, perhaps,
frequently, often, majority, minority, usually, all but one
Standard Form
• Some S is P
• Some politicians(S) are liars(P)
4. O – Proposition
Main Identity
• Some…..not
Other words to identify
• Few, hardly any, scarcely any, seldom
Standard Form
• Some S is not P
• Some politicians(S) are not liars(P)
