Assumed safety vs Proven safety

DescriptionThis paper examines the recurring distinction between assumed safety and proven safety in safety-critical systems. Across multiple sectors, safety is frequently treated as an inferred condition based on design intent, certification status, policy compliance, or historical performance, rather than as a state evidenced at the point of need.The paper sets out a comparative framework distinguishing what is commonly assumed to be safe from what is provable at the moment safety is relied upon. It identifies recurring evidentiary patterns observed in post-incident inquiries, regulatory reviews, and legal proceedings, where safety assumptions are revealed to lack contemporaneous proof.The analysis is non-prescriptive and does not propose technologies, systems, or solutions. Its purpose is to clarify the governance implications of relying on assumed safety, and to articulate why evidentiary sufficiency at the moment of reliance is central to accountability, assurance, and decision-making in safety governance.