 Although this is already quite a strong conclusion, it does not yet rise to the level of full-blown necessitarianism with respect to modes. There are still at least three possible sources of contingency for the maximally full world of modes, each of which would be compatible with POP. Alternative possibility 1 (AP1): There could have been a different collection of modes, equal in size to the actually existing collection, but with entirely different members. Alternative possibility 2 (AP2): For some proper subset of the collection of actually existing modes, there could have been  a different, equinumerous proper subset of modes instead. Alternative possibility 3 (AP3): One or more of the actual modes could have had different characteristics than it in fact has.