Selective permeability holds that people’s distinct capacities allow them to do different things in a space, making it unequally accessible. Though mainly applied to urban geography so far, we propose selective permeability as an affordance-based approach for understanding diversity in education. This has advantages. First, it avoids dismissing lower achievements as necessarily coming from “within” students, instead locating challenges in the environment. This implies that settings (not just people) need remedial attention, also raising questions about normative judgments in disability nomenclature. (...) Second, affordances can be negotiated in numerous ways to reach a goal, analogously to how people with missing arms have learned to drive with their feet, so restrictive problem-solving methods are often counterproductive. Third, our approach illuminates how cultural factors ranging from gait styles to language and hence group coordination modulate action possibilities, so that cultural groups may encounter objectively different affordances in the same classroom. But fourth, while fit with environment allows for skill refinement, non-fit can contribute to growth situations, which suggests a degree of selective closure can be desirable. Throughout, we argue social constructs—including educational ones—are literally built or enacted barriers or openings that have reality in environments in the same way that affordances do. (shrink)