The Impossibility of an Actually Infinite Future: A Theory-Neutral Argument from Structural Incoherence

Arguments against an infinite past often rely on the impossibility of traversing an actual infinite. This paper develops a parallel argument against an actually infinite future without appealing to controversial grounding principles or any single theory of time. It argues that dynamic theories of time generate a tension between finitude and potential infinitude when they deny an actually infinite future, while static theories face the same structural problems for an infinite future that the Kalam argument raises for an infinite past, since the past–future asymmetry collapses within a block universe. The paper further argues that potential infinity is not a stable middle ground. It concludes that the combination of a finite past and an infinite future is incoherent across all major theories of time and that a finite temporal totality is the only consistent resolution.