Full Idea
In the full exposition of Putnam's mechanism for generating the necessary truth that water is H2O, we find that the mechanism employs a certain nontrivial general principle of essentialism concerning liquid substances as a crucial premise.
Gist of Idea
Putnam smuggles essentialism about liquids into his proof that water must be H2O
Source
comment on Hilary Putnam (The Meaning of 'Meaning' [1975]) by Nathan Salmon - Reference and Essence (1st edn) 6.23.1
Book Reference
Salmon,Nathan: 'Reference and Essence (2nd ed)' [Prometheus 2005], p.184
A Reaction
This charge, that Kripke and Putnam smuggle the essentialism into their semantics, rather than deriving it, is the nub of Salmon's criticism of them. It seems to me that a new world view emerged while those two where revising the semantics.