According to the Doctrine of Divine Conservation, the world could not endure through time were God not actively sustaining its existence. An alternative to the conservationist view is one according to which the existence of whatever is the fundamental material of our universe is characterized by inertia, so that its continuance stands in no need of active causal intervention by some other being. In this article I develop in some detail the Doctrine of Existential Inertia and reply to some of (...) the objections brought against it by conservationists. (shrink)