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.
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'."