 A major focus of the debate within the SEF approach has been the second kind of case – cases of what Menzies calls ‘counterfactual isomorphs’ (Menzies 2017), where two different scenarios have isomorphic causal models and yet our judgements about what causes what differs in the two different scenarios. For example, consider a case of ‘bogus prevention’ (Hiddleston 2005): believing that Killer has previously poisoned Victim’s coffee, Bodyguard puts an antidote into it. However, in fact Killer had a change of heart and didn’t poison the coffee. Victim survives – but his survival was not, surely, caused by Bodyguard’s action, for there was no threat to Victim’s life that Bodyguard neutralized. It is possible, however, to construct a causal model of this case that is isomorphic to a standard case of symmetric overdetermination: Billy and Suzy are throwing rocks again, but this time both of their throws hit the bottle at the same time, so that each is sufficient for its shattering and neither hit pre-empts the other. In that case (allegedly), we identify both Billy’s and Suzy’s throws as causes of the bottle’s shattering (Blanchard and Schaffer 2017: 185–6).