Absences pose a dilemma for theories of causation. Allowing them to be causes seems to make theories too permissive (Lewis, 2000). Banning them from being causes seems to make theories too restrictive (Schaffer, 2000, 2004). An increasingly popular approach to this dilemma is to acknowledge that norms can affect which absences count as causes (e.g., Thomson, 2003; McGrath, 2005; Henne et al., 2017; Willemsen, 2018). In this article, I distinguish between two influential implementations of such ‘abnormality’ approaches and argue that (...) so-called ‘double-prevention mechanisms’ provide counterexamples against both. (shrink)