 Another account of strongly emergent autonomy posits fundamentally new powers, forces, or laws directly associated with the emergent property of a complex object or system (O’Connor 1994, Silberstein &amp; McGeever 1999, Wilson 2002, and O’Connor &amp; Wong 2005). “Fundamental” here signifies that the power is not the resultant of any generalized kind of summation on the powers of the object’s constituents relative to the relational structure in which they are embedded. One variation on this basic account concerns the way emergents depend on their bases. One common variant holds that emergent features are synchronically nomologically necessitated by the base-level structure, where the necessitation, while law-governed, is not via causal production (Broad 1925, Silberstein &amp; McGeever 1999, and Wilson 1999 and 2002). An alternative (naturally suited to a neo-Aristotelian causal powers metaphysics) maintains that emergent features are diachronically caused by a plurality of micro-properties acting jointly (perhaps together with other emergent features), under the triggering condition of the micro-properties’ being appropriately structurally organized (O’Connor &amp; Wong 2005). This alternative can allow that, even granting that causal necessity is a species of metaphysical necessity, the supervenience of strongly emergent features on base phenomena will fail in (at least possible) scenarios in which the causal dependence between either base and emergent features or emergent features and their effects is non-deterministic. That said, whether supervenience does in fact fail for any actual cases of strong emergence is an empirical question (on which, see  section 5.2).