The Double-Slit Experiment as a Resolution-Limited Distinguishability Test

This paper examines the double-slit experiment as a bounded supporting case for the concept of resolution as structural accessibility developed in Resolution Levels and Structural Accessibility: A Structure-First Framework for Physical Interaction Without Dimensional Inflation. The analysis remains within standard quantum mechanics. In two-path interference, observable fringe visibility depends on whether the alternative paths remain coherent or become physically distinguishable through coupling to a detector, marker, or environment. Increasing path distinguishability is associated with decreasing interference visibility, without requiring any change in the underlying spatial dimensionality of the experiment. Within the Resolution framework, this provides a simple physical example of interaction-dependent accessibility: the underlying structure may remain unchanged while the set of distinctions that can participate as independently resolved alternatives changes with coupling. The paper does not propose a new quantum formalism, a mechanism for wavefunction collapse, or a unique interpretation of quantum mechanics. Its role is narrower: to show that an established quantum-mechanical result is consistent with the classificatory distinction between structure itself and structure accessible to a given interaction regime. This revised version replaces the earlier broader interpretation with a deliberately limited supporting analysis centred on distinguishability, coherence, coupling, and structural accessibility.