 By rejecting strong metaphysical supervenience, Rosen must reject the Sidgwickian explanatory idea suggested in  Section 2:  that ethical supervenience reflects a commitment to rejecting brute ethical contingency. One worry about Rosen’s strategy is that by embracing such contingency one permits an especially objectionable form of moral luck (Dreier, 2019). On Rosen’s view, there may be a world that is relevantly non-ethically identical to this one in which my counterpart is ethically quite different: in the extreme case, it raises the specter that the specific loving attitudes that I bear towards my child might have been evil, or even just a matter of utter ethical indifference. But it is hard to believe that I am lucky that the very attitudes that I possess count as commendable rather than awful. (See Lange 2018 for another important challenge to Rosen’s argument).