Two-dimensionalism provides an analysis of the semantics of words and sentences that makes sense of this possibility.
The theory was first developed by Robert Stalnaker, but it has been advocated by numerous philosophers since, including David Chalmers.
[1][2] The primary intension of a word or sentence is its sense, i.e., is the idea or method by which we find its referent.
The primary intension of "water" might be a description, such as watery stuff or "the clear, drinkable liquid that fills oceans and lakes."
[3] Two-dimensional semantics has been used by David Chalmers to counter objections to the various arguments against materialism in the philosophy of mind.
[4] The reason Chalmers employs two-dimensional semantics is to avoid objections to conceivability implying possibility.
Chalmers replies that it is 1-possible that water wasn't H2O because we can imagine another substance XYZ with watery properties, but it's not 2-possible.
[5] Soames argues that two-dimensionalism stems from a misreading of passages in Kripke (1980) as well as Kaplan (1989).