Philosophers treat time travel as a lens for examining causality, free will, and the nature of reality. The apparent paradoxes—such as killing one's own grandfather—force a reevaluation of whether the past is fixed or malleable. Proponents of the Novikov self‑consistency principle argue that the universe only allows histories that are internally consistent, preserving determinism despite the appearance of freedom. Advocates of the many‑worlds interpretation see time travel as a branching process, where each intervention creates a new timeline, thereby sidestepping paradoxes but raising questions about identity and moral responsibility across branches. These debates reveal that time travel is as much a conceptual challenge as a physical one.