They were originally proposed through the example of Hesperus and Phosphorus being the same object, in lectures that would become Naming and Necessity.
The theory of these objects was informally introduced through the use of "tags" by Ruth Barcan Marcus in her 1961 article "Modalities in Intensional Language." David Kaplan presented a theory of these philosophical ideas in a lecture later published as "Dthat" shortly after they were formally introduced in a lecture series by their best-known popularizer. One of the uses of these philosophical concepts is to demonstrate the existence of necessary a posteriori propositions and contingent a priori propositions, and the inventor of this term proposed that proper names and natural kinds such as water are examples of these. They were originally proposed through the example of Hesperus and Phosphorus being the same object, in lectures that would become Naming and Necessity. FTP, identify these philosophical concepts coined in name by Saul Kripke, which refers to a description that has the same reference in every possible world.
The theory of these objects was informally introduced through the use of "tags" by Ruth Barcan Marcus in her 1961 article "Modalities in Intensional Language."
{rigid designator}s