 Defenders of the counterfactual analysis of “cause-in-fact” are not bereft of replies to these four objections, but rather than pursuing this further we shall move on to discuss other tests that have been substituted for the counterfactual test in an attempt to avoid these four problems. With regard to the problem posed by the overdetermination cases, the best known alternative is to propose an “INUS” (an Insufficient but Necessary element of an Unnecessary but Sufficient set) test (Mackie 1980) or a “NESS” (Necessary Element of a Sufficient Set) test (Wright 1985b; 2013): an event c causes an event e if and only if c is a necessary element in a set of conditions sufficient for e where the set itself need not be necessary for e. It is the stress on sufficiency in these tests that is supposed to end-run the overdetermination problems. In the concurrent cause cases—the two sufficient fires joining to burn the victim’s house—each fire is said to be a necessary element of its own sufficient set, so each fire is a cause. In the preemptive case—the fires do not join and one arrives first before the second can get there to do the job—the first fire is a necessary element of a sufficient set, and so is the cause; the second fire is not, because it is not thought to be part of a set that is sufficient at the time of the destruction (absent from its set is the existence of a house to be burned).