With some of the propositions from the literature on 'policy enactments' as a backdrop, this paper addresses the circulation of a research policy innovation and its effects on the knowledge territory of an unlikely profession. Specifically, I show how the Research Excellence Frameworks' impact policy in the UK was an object first managed by policymakers but later released as an object of concern for professional academics, including philosophers. I follow 'impact' through texts, events and testimonies about its doings with a special interest in its creation, its polemical encounter with philosophers, its management and issues about its definition and the assessment criteria used and experienced by philosophers. I conclude with some remarks on the effects that the circulation and writing of impact case studies had on producing a social valorisation and attachment to impact, even amongst philosophers.