Full Idea
'Dthat' is Kaplan's indexical operator; it operates on a given singular term, φ, and makes it into a rigid designator of whatever φ designates in the original context.
Gist of Idea
'Dthat' operates to make a singular term into a rigid term
Source
Alan Sidelle (Necessity, Essence and Individuation [1989], Ch.6 n11)
Book Reference
Sidelle,Alan: 'Necessity, Essence and Individuation' [Cornell 1989], p.178
A Reaction
I like this idea a lot, because it strikes me that referring to something rigidly is a clear step beyond referring to it in actuality. I refer to 'whoever turns up each week', but that is hardly rigid. The germ of 2-D semantics is here.
Related Idea
Idea 17003 Kaplan's 'Dthat' is a useful operator for transforming a description into a rigid designation [Kripke]