In Kant’s idealism, all spatiotemporal objects depend on the human mind in a certain way. A central issue here is whether the existence of spatiotemporal things requires that these things are, at least at some point, objects of some actual experience or of a merely possible experience. In this essay, I argue (on textual and philosophical grounds) for the latter view: spatiotemporal things exist (or spatiotemporal events occur) if they are objects of a (suitably qualified) possible experience.