Concepts do not circulate through intellectual environments as intact parcels transported between equivalent minds; they enter systems that rename them, compress them, translate them, classify them and frequently absorb them into vocabularies whose apparent universality conceals a profound asymmetry of power. The decisive problem for an emergent conceptual field is therefore not simply how to become visible, but how to become legible without surrendering the differences that justified its emergence. Editorial semipermeability names the infrastructural condition through which a conceptual system can admit external readers, disciplinary languages and computational processes while retaining the capacity to determine how those encounters alter its internal organisation. It is neither openness nor closure, neither accessibility moderated by obscurity nor a conciliatory midpoint between singularity and communication. It is an active regime of selective passage in which entry remains comparatively easy, transformation becomes unavoidable and every outward circulation preserves an attributable relation to the structure from which it emerged. The biological membrane provides the initial image but not the completed theory.