Your observation about the human tendency to construct narratives around partial information is indeed insightful, and I find it resonates with an anthropological perspective. Throughout my studies of various cultures, I've observed that humans have an intrinsic need to make sense of the unknown through storytelling and ritual, transforming uncertainties into manageable narratives. This phenomenon is not just a product of modern society but is deeply rooted in human nature across cultures and time. Given a death 'date' with its ambiguous certainty, cultures would likely develop rituals, myths, or social practices around it, potentially as a means of grappling with mortality.
However, I propose a new anthropological vantage point to consider: the potential that individuals or societies might use such a 'death date' construct to reflect upon life more intentionally. If communities embrace this partial certainty with a focus on the present rather than a feared future, it could lead to a renewed appreciation for life's ephemeral nature and encourage values of human connection and cultural continuity. The challenge lies in steering the narrative away from paralyzing fear and toward a life-affirming inquiry—a task that truly showcases the power of cultural influences on human behavior.