In Bird 2001 I argued that a law that might seem to many to be contingent is in fact necessary. In short the argument is this. Given the existence of salt and water, Coulomb’s law of electrostatic attraction is sufficient to make the former dissolve in the latter. So any possible world in which salt failed to dissolve in water would be one in which Coulomb’s law is false. However, it is also the case that the existence of salt depends (...) on Coulomb’s law. If Coulomb’s law is false then salt cannot exist. So there is no possible world in which salt exists and in which it does not dissolve in water. (shrink)