Teaching Reality through Spacetime: Philosophical Narratives of Light Cones and Worldlines

This paper proposes a geometric–narrative approach to teaching reality through Einstein’s concept of spacetime. Instead of emphasizing calculus, we employ light cones and worldlines as a visual grammar to articulate the causal boundary, relational “now,” and the continuity of identity. Three ideas are framed in a lay-friendly yet accurate manner: (i) “now” is understood as a frame-dependent spacelike slice; (ii) identity is treated as a trajectory, sustained by proper time and the notion of geodesics; (iii) agency is defined within the causal boundary, encompassing planning and responsibility that extend from the causal past into the causal future. The practical contribution of this paper is a ready-to-use teaching package in the format of three ninety-minute sessions, integrating clean vector diagrams, peer-instruction activities, short narrative tasks, and low-tech variants for resource-limited contexts. The assessment design—diagnostic, formative, and summative—is aligned with success indicators that evaluate understanding of causality, worldline reading, and reflective argumentation. Conceptually, the manuscript interlinks physics, philosophy, and education to cultivate reflective science literacy. Students are not only enabled to calculate, but also to contemplate the meaning of reality, causality, and self.