Full Idea
The single Fregean intension has fragmented into two: a primary intension ("watery stuff") that fixes reference in the actual world, and a secondary intension ("H2O") that picks out reference in counterfactual possible worlds.
Gist of Idea
Meaning has split into primary ("watery stuff"), and secondary counterfactual meaning ("H2O")
Source
David J.Chalmers (The Conscious Mind [1996], 1.2.4)
Book Reference
Chalmers,David J.: 'The Conscious Mind' [OUP 1997], p.59
A Reaction
No one actually performs this schizoid double operation, so this is theory disconnected from life. What is the role of 'H2O' in the actual world, and 'watery stuff' in the others?