The Ontological Asymmetry of Time Travel: Conceptual Clarification and the Causal Stickiness Framework

This paper is primarily an exercise in conceptual clarification. Existing discussions of time travel often conflate several distinct issues: causal necessity and causal stickiness, prediction and travel to the future, physical absence and ontological rupture, single-history consistency and worldline fission. I situate these distinctions against the background of Lewis's analysis of time travel paradoxes, the Novikov self-consistency principle, open future theories, branching time, and debates about personal identity. On this basis, I propose an explanatory framework organized around the notion of causal stickiness: the structural closeness between an event and the time traveler's own node in a causal network. In backward time travel, causal stickiness appears as resistance to alteration; in forward time travel, it appears as cross-worldline divergence. I do not claim to provide a complete formal theory of causal stickiness, nor do I claim that its dimensions admit a unique linear aggregation. Path length, number of causal paths, directness of dependence, and structural proximity may carry different weights in different cases. My weaker claim is that in central cases, such as the grandfather paradox, these dimensions point in the same direction, making judgments of high stickiness robust; in marginal cases, the degree of stickiness may remain contestable. I then argue that backward travel is best understood as modification of an already actual causal structure, whereas forward travel is best understood, on a strong open-future reading, as generation from an as-yet indeterminate region, and on a weaker eternalist reading, as transition between worldlines with different initial conditions. The deeper cost of time travel is not paradox as such, but an ontological rupture between the subject and its original causal position.