 Some deny that cases of prevention are genuinely causal (see Aronson 1971; Dowe 2000; Beebee 2004a; and Hall 2004). This response could be further justified with worries about absences being effects (recall  §1.1.2).  However, there are additional worries about the cases which Hall (2004) calls “double prevention”. In these cases, c prevents d, and, if d had happened, then d would have prevented e. So c prevents a preventer of e. For instance: Blofield launches a cyber attack on Europe’s electrical grid, plunging the continent into the dark. Had Bond not shot down the missile, it would have prevented Blofield from carrying out the cyber attack. So Bond prevented a potential preventer of the cyber attack. Here, there is an inclination to say that Bond was an (inadvertent) cause of the cyber attack. However, there is no connecting process leading from Bond to the cyber attack—there is no relevant energy-momentum flow, mark transmission, or persisting trope connecting them.