 Priority pluralists can also use modalized versions of 28 (“Necessarily, basic objects evolve by the fundamental laws”) plus the possibility of island universes to pose a problem for the priority monist (Schaffer 2013: 83, Baron and Tallant 2016, Siegel 2016). An island universe in the sense relevant to the argument is not a spatiotemporally disconnected universe with multiple disconnected regions (as discussed by Lewis 1986: 71–3), but a causally disconnected universe with multiple causally/nomically separate closed systems. The counter-argument (compare Baron &amp; Tallant 2016: 590) is that such island universes are possible, and so—given a modalized version of 28—scenarios with a plurality of basic objects are possible, and so priority monism is not necessarily true. Tack on the premise that if priority monism is true then it is necessarily true, and it follows that priority monism is false.