Chalmers has published works on the "theory of reference" concerning how words secure their referents. He, together with others such as Frank Jackson, proposes a kind of theory called two dimensionalism arguing against Saul Kripke. Before Kripke delivered the famous lecture series Naming and Necessity in 1970, the descriptivism advocated by Gottlob Frege and Bertrand Russell was the orthodoxy. Descriptivism suggests that a name is indeed an abbreviation of a description, which is a set of properties or, as later modified by John Searle, a disjunction of properties. This name secures its reference by a process of properties fitting: whichever object fits the description most, then it is the referent of the name. Therefore, the description is seen as the connotation, or, in Fregean terms, the sense of the name, and it is via this sense by which the denotation of the name is determined.