Descartes’ doctrine of the creation of eternal truths seems to claim that there is a class of necessary truths which are, nevertheless, possibly false. In short, these are truths concerning the essences of created things, and so are necessary: yet God, having full voluntary control over the creation of said essences as part of his voluntary control over creation in general, could have failed to create some essences or created them otherwise than he did. This leads to a famous difficulty in interpreting Descartes modal metaphysics. In this talk, I develop an interpretation according to which Descartes countenances two modalities, one constrained by the actual essences God creates (inner modalities), and the other not so constrained (outer modalities). I present some textual evidence to support this reading and develop a model theory capturing the logical behaviour of the modalities.