 List and Spiekermann begin by appealing to the difference-making or counterfactual conception of causation, which asserts that “a property C (within a system of interest) is the cause of another property E if and only if C systematically makes a difference to E” (2013: 636). By implication, a supervenient social property, S, qualifies as a cause of E, when S makes a systematic difference to E. This means that, other things being equal, if S occurred E would do so too, and that if S did not occur, then neither would E. Now assume that S is microrealization-robust: S would also have brought about E if it had been realized by a compound of individualist properties other than the one that actually realizes it. In situations of this sort, the compound of individualist properties that realizes S does not make a systematic difference to E. While it is the case that if the compound occurred then so would E, it is not the case that if the compound did not occur, E would not occur either. Hence it is S, rather than the compound of individualist properties realizing S, that qualifies as the cause of E. List and Spiekermann underline that in these circumstances, a holist explanation—that is, an explanation describing how a given supervenient social property brought about some effect—is needed.