Generally, a proposition is a statement, a sentence that makes a claim such as "This water tastes bad."
There are four kinds of propositions,
labeled A, E, I, and O.
An
'A' proposition claims that "All A are P."
An 'E' proposition claims that "
No A are P."
An 'I' proposition claims that "Some A are P."
An
'O' proposition claims that "Some A are
not P."
Propositions are used in everyday language. A simple sentence can be a proposition. A proposition is labeled for the purpose of determining its
validity, its truthfulness, against other statements in logical arguments when compared to other statements in that argument.
"This water tastes bad" would be an example of an 'A' proposition, because the speaker is including all of 'this' water in his claim.
Example:
A proposition: "A restaurant is not a clean place." "All cats are
felines."
E proposition: "Not one smile is on any of their faces." "No cats are canines."
I proposition: "Some candy is
sickeningly sweet." "Some cats are in the species called 'lion'."
O proposition: "Some days are not good days around here." "Some cats are not in the
genus called 'Panthera'."