The appeal to the necessary a posteriori is on the surface an attractive one, but it is also controversial. One problem arises from the fact that Kripke’s idea that there are necessary and a posteriori truths can be interpreted in two rather different ways. On the first interpretation — I will call it the derivation view — while there are necessary a posteriori truths, these truths can be derived a priori from truths which are a posteriori and contingent. On the second interpretation — I will ca