Salt does dissolve in water, but not necessarily
in question are the charges of the water dipoles and sodium atoms). But it does not follow that in any possible world where Coulomb’s law (or something reasonably similar to it) is false, the two relationships (that is, the relationship between the sodium and chlorine ions on the one hand, and the relationship between the water dipoles and the sodium atoms on the other) fall together: the failure of just one of the relationships (the relationship between the water dipoles and the sodium atoms) is enough to make Coulomb’s law (or something reasonably similar to it) false. The world w described above is, admittedly, a rather peculiar kind of world. But I see no reason to deny that it is a metaphysically possible world. One might wonder whether the disjunctive ‘law’, either F = -e0(pq/r) or F = -e0(pq/r), really deserves to be called a law. But that isn’t to the point. w is regular enough to contain genuine salt, yet irregular enough for salt (sometimes) to fail to dissolve in water. Whether or not the disjunction that correctly describes the behaviour of salt when dropped in water deserves to be called a law, w is a possible world where ‘salt dissolves in water’ is false.