This paper attempts to resolve the apparent conflict between Descartes’ commitments to the creation doctrine and the necessity of eternal truths by elaborating different conceptions of necessity in Descartes’ framework. More specifically, I argue that the fact that Descartes concedes the necessity of eternal truths does not compel him to assert the impossibility of their negation. Necessity, for Descartes, rather means immutability. Descartes distinguishes two kinds of immutable truths. While truths about God’s essence are absolutely immutable, truths about the essences (...) of God’s creation are conditionally immutable, i.e., they can change if God’s will changes. Since there are different kinds of eternal truths, they express different kinds of necessity as well, namely conditional and absolute necessity. After I clarify these two kinds of necessity, I explain how Descartes coherently maintains both that eternal truths are necessary and that God could have created eternal truths otherwise without undermining their necessity. (shrink)