The Sandbox Paradox

The Sandbox Paradox examines the dual role of system boundaries in observation, explanation, and design. A boundary can create a useful and controllable domain of analysis, yet the same boundary can distort the phenomenon when it excludes relevant transfers, causal history, or discriminating variables. The study distinguishes between closed-process, interfaced, interpretive, and functional sandboxes, and introduces Boundary-Induced Indistinguishability (BII): a condition in which the selected spatial, temporal, hierarchical, or interpretive boundary removes the information required to distinguish between competing mechanisms. The framework connects boundary placement to apparent sources and sinks, subsystem accounting, dynamic membership, model identifiability, and boundary-sensitive conclusions. A practical boundary-audit procedure is proposed for testing whether a result survives reasonable changes in system extent, observation window, interface accounting, and level of aggregation. The framework is presented as a domain-independent methodological concept study rather than as proof of any particular physical, economic, or computational theory. Its purpose is to support critical testing, refinement, and domain-specific falsification.