The idea that truths of this type can be a posteriori was pioneered in a three-lecture series given at Princeton in 1970, using the example "Water is H2O".
Quine rejected the use of this property as an operator on open formulae because such usage leads to "referentially opaque" contexts. A distribution axiom symbolized by a boldfaced K applies the distributive property to this property. In some formulas named for female Yale philosopher Ruth Barcan Marcus, this property's operator is symbolized by a square; that square symbolizing this property also appears in axiom (*) S5 before a diamond. A proposition which is true in all possible worlds has this property. The idea that truths of this type can be a posteriori was pioneered in a three-lecture series given at Princeton in 1970, using the example "Water is H2O". For 10 points, name this type of truth contrasted with contingent truths, which was discussed by Saul Kripke along with "Naming."
Quine rejected the use of this property as an operator on open formulae because such usage leads to "referentially opaque" contexts.
necessary truths [or necessary propositions; or necessity/ies; or "it is necessary that"; or necessity operator]