Please join us on February 6th, 2026 for a department talk with Elís Miller, who is a Visiting Scholar at Penn following postdoctoral positions at Brown University and the University of Vermont. 

Title: Rational Agency In A Fixed World: time travel, inevitability, and moral agency

Abstract: Time-travel puzzles do more than test our intuitions about the past—they expose a tension between knowledge and rational agency. If an agent knows that a past catastrophe occurred and that the past is fixed, can it still be rational to try to intervene? I argue that knowledge of inevitability can collapse practical deliberation by rendering outcomes action-insensitive. This reflects a problem about metaphysical fixedness. The problem extends beyond time travel. In ordinary moral contexts— structural injustice, entrenched harm, historical wrongs—agents often experience the present as fixed, accompanied by the sense that there is nothing they can do. I suggest that this form of moral paralysis reflects a further problem—one of epistemic fixedness . I further argue that while certainty undermines agency, ignorance can preserve the possibility of rational moral action.