 The coincidence objection to the counterfactual test yields a fourth modification to that test. In cases like that of the negligently speeding train that, because of its speed, arrives at just the place where a falling tree hits it (Berry v. Borough of Sugar Notch), one should not ask, “But for the act of driving would the train have been hit?” Rather, one should isolate that aspect of the act that made it negligent—speeding, not the act itself—and ask whether that aspect was necessary to the train having been struck.  And arguably driving in excess of the speed limit (“speeding”) was not necessary for the impact because any speed above as well as below the speed limit would have resulted in no impact on the train.  Speeding, in other words, wasn't necessary, only the exact speed at which the driver in fact drove.  Asking after the necessity of qualities of acts like speeding is called the “aspect cause” version of the counterfactual test (Keeton 1963; Wright 1985b).