What do we really know about safety? The volume of critique directed at current safety practice, and the academic disagreements about epistemology and research methods suggest a lack of consensus about what safety is, how safety can be investigated, and how safety can be achieved. Further, recruitment advertisements, education programs and accreditation schemes show no clear industry position on the level or type of education a safety practitioner needs. This paper suggests that divisions between safety practice and research communities can be explained by different answers to the primary research question “Why do accidents happen?” The paper explores how these answers manifest as distinct schools of thought which use a common language to conceal fundamental differences in the understanding and practice of safety.