On whether some laws are necessary

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. When fully elaborated the argument needs to take into consideration the thought that salt might after all be permitted to exist in a world in which Coulomb’s law (as it is found in the actual world) is false. A close cousin of Coulomb’s law might be true in that world, sufficiently close to allow salt to exist. But the cousin might not be close enough to require dissolving to take place. I suggested that such a world will not exist, given what we know of chemistry. Our knowledge of chemistry allows us to predict what would happen were the laws slightly different. (This sort of thought