[1] The thesis is best known for its association with Saul Kripke, who published it in 1971,[2] although it was first derived by the logician Ruth Barcan Marcus in 1947,[3] and later, in simplified form, by W. V. O. Quine in 1953.
[4] The derivation in Kripke's 'Identity and Necessity' is in three steps: The first premise is simply postulated: every object is identical to itself.
In the later Naming and Necessity, Kripke suggested that the principle could be derived directly, assuming what he called rigid designation.
Some examples of rigid designators include proper names (i.e. ‘Richard Nixon’), natural kind terms ( i.e. ‘gold’ or ‘H2O’) and some descriptions.
According to Kripke, the proper name "Richard Nixon" can only be used rigidly, but the description "the man who won the 1968 election" can be used non-rigidly.