 This analysis has some surprising consequences when combined with certain other commitments of Armstrong’s view. For example, Armstrong holds that any two universals have a conjunction, which he identifies with their mereological fusion. Given the proposed analysis, this entails that the conjunction of any two perfectly natural properties is itself perfectly  natural.[41]  This conflicts with the claim that no perfectly natural property supervenes on all the rest. If one wanted to hold on to that claim, one might instead analyse ‘perfectly natural property’ as ‘property corresponding to some mereologically simple  universal’.[42]  Note however that for Armstrong it is an open question whether there are any mereologically simple universals, and thus whether the properties corresponding to mereologically simple universals form a supervenience base for everything.