At first glance, every metaphysics of laws can be combined with every ontology of time. In contrast, the paper intends to show that Humeanism requires eternalism and that Power metaphysics must presuppose an existentially dynamical view of temporal existence, i.e. growing block or presentism. The presented arguments turn out to be completely independent of whether the laws of nature are deterministic or probabilistic: the world is non-productive and static or productively dynamical, the future be ‘open’ or not.