Invariance as the Minimum Condition for Thinghood

This paper proposes a simple structural principle. Any entity that can be identified as a thing carries at least one invariant across change. Invariance here refers to a property, relation, or constraint that remains stable long enough for the entity to be distinguished, tracked, or recognized. This principle applies across physical, informational, cognitive, and experiential domains. The argument does not introduce a new mechanism. It makes explicit a condition already assumed wherever objects, processes, or events are treated as real. By foregrounding invariance as the minimum requirement for thinghood, the paper clarifies the shared structure underlying identity, persistence, and recognition.