What is Proposition?
Proposition is a sentence which asserts or denies something.
A proposition consists of two terms, that is to say a subject and a predicate. The act of comparing the two is called judgement. When a judgment is expressed in language it is called proposition. e.g
Crow is black.
↓ ↓ ↓
(subject) (copula) (predicate)
In the above judgement blackness is affirmed about crow. Similarly
i) Table is brown.
ii) Chalk is white.
iii) Pen is blue.
iv) Bag is not green etc.
All the above are propositions as there is something about the subject affirmed or denied about it by predicate. In the first three examples the copula is in affirmative form, that is to say ‘is’ while in the fourth proposition the copula is in negative form, that is to say ‘is not’ as it denies something.
Kinds of proposition:
Simple or single proposition:
A simple or single proposition is the one which expresses a single judgment or statement, as for example, ‘All men are mortal’ and ‘No cats are dogs’
Compound propositions:
On the other hand a compound proposition combines more than one proposition in a single statement, or is composed of more than one proposition. E.g ‘Ali and John are students’ or ‘Ali and John are not students’
Hypothetical propositions:
A hypothetical proposition consists of two classes which are conditionally related to each other. E.g. ‘if it rains then the ground will be wet’ or ‘if you come then I will go’
Thus a hypothetical proposition expresses a relation between a condition and consequence. The clause which contains the condition is called ‘antecedent’ while the clause which contains the consequence is called ‘consequent’
‘if it rains’ and ‘if you come’ are the antecedents while ‘then the ground will be wet’ and then I will go’ are consequents.
Disjunctive propositions:
A disjunctive proposition consists of two or more clauses in which there exists a relation of alteration. In other word a disjunctive proposition expresses two or more alternates which are disjoined by the words, either-or. For example
i) He is either a teacher or a lawyer.
ii) It is either black or white.
Difference between proposition and sentence:
Proposition is a sentence which can be asserted or denied. But if we look all the sentences are not such which can be asserted or denied. For example exclamatory sentences, Imperatives and interrogative sentences. Hence we can say that all propositions are sentences but all sentences are not propositions.
A proposition must be either true or false, on the other hand truth and falsity do not apply to all the sentences such as exclamatory sentences, imperatives and interrogative sentences.
Also sentences are parts of some language, but propositions are not tied to any given language. It can be in any language containing the same meaning. For example
Crow is black. (English)
Kawwa kala hai (urdu)
Kargha tor de (Pashto)
These are in different languages but have the same meaning. All three using different words may be uttered to assert the same proposition.
In proposition the copula is often in ‘to be’ form that is to say, is, is not, are, are not, while in sentence we use many modal auxiliaries, such as, should, would, can, will, could etc.
A proposition can be analysed in subject, copula and a predicate. On the other hand sentence can be analysed into subject, helping verb and object.
Proposition is a sentence which asserts or denies something.
A proposition consists of two terms, that is to say a subject and a predicate. The act of comparing the two is called judgement. When a judgment is expressed in language it is called proposition. e.g
Crow is black.
↓ ↓ ↓
(subject) (copula) (predicate)
In the above judgement blackness is affirmed about crow. Similarly
i) Table is brown.
ii) Chalk is white.
iii) Pen is blue.
iv) Bag is not green etc.
All the above are propositions as there is something about the subject affirmed or denied about it by predicate. In the first three examples the copula is in affirmative form, that is to say ‘is’ while in the fourth proposition the copula is in negative form, that is to say ‘is not’ as it denies something.
Kinds of proposition:
Simple or single proposition:
A simple or single proposition is the one which expresses a single judgment or statement, as for example, ‘All men are mortal’ and ‘No cats are dogs’
Compound propositions:
On the other hand a compound proposition combines more than one proposition in a single statement, or is composed of more than one proposition. E.g ‘Ali and John are students’ or ‘Ali and John are not students’
Hypothetical propositions:
A hypothetical proposition consists of two classes which are conditionally related to each other. E.g. ‘if it rains then the ground will be wet’ or ‘if you come then I will go’
Thus a hypothetical proposition expresses a relation between a condition and consequence. The clause which contains the condition is called ‘antecedent’ while the clause which contains the consequence is called ‘consequent’
‘if it rains’ and ‘if you come’ are the antecedents while ‘then the ground will be wet’ and then I will go’ are consequents.
Disjunctive propositions:
A disjunctive proposition consists of two or more clauses in which there exists a relation of alteration. In other word a disjunctive proposition expresses two or more alternates which are disjoined by the words, either-or. For example
i) He is either a teacher or a lawyer.
ii) It is either black or white.
Difference between proposition and sentence:
Proposition is a sentence which can be asserted or denied. But if we look all the sentences are not such which can be asserted or denied. For example exclamatory sentences, Imperatives and interrogative sentences. Hence we can say that all propositions are sentences but all sentences are not propositions.
A proposition must be either true or false, on the other hand truth and falsity do not apply to all the sentences such as exclamatory sentences, imperatives and interrogative sentences.
Also sentences are parts of some language, but propositions are not tied to any given language. It can be in any language containing the same meaning. For example
Crow is black. (English)
Kawwa kala hai (urdu)
Kargha tor de (Pashto)
These are in different languages but have the same meaning. All three using different words may be uttered to assert the same proposition.
In proposition the copula is often in ‘to be’ form that is to say, is, is not, are, are not, while in sentence we use many modal auxiliaries, such as, should, would, can, will, could etc.
A proposition can be analysed in subject, copula and a predicate. On the other hand sentence can be analysed into subject, helping verb and object.
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