Full Idea
The rigid designator approach to essentialism has essentialist assumptions. ..The necessity of identity is built into the very conception of a rigid designator,..and Leibniz's Law is presupposed...and necessity of origin presupposes sufficiency of origin.
Gist of Idea
Rigid designation has at least three essentialist presuppositions
Source
David S. Oderberg (Real Essentialism [2007], 1.1)
Book Reference
Oderberg,David S.: 'Real Essentialism' [Routledge 2009], p.5
A Reaction
[compressed. He cites Salmon 1981:196 for the last point] This sounds right. You feel happy to 'rigidly designate' something precisely because you think there is something definite and stable which can be designated.