  The theorist who thinks that clouds are just fusions of water droplets cannot accept this principle, or they will conclude that every oi is a cloud, since for them each oi is of the right category. On the other hand, Johnston himself cannot accept it either unless he denies there can be another object c´ which is in a similar position to c, and is of the same category as c, but differs with respect to which water droplets constitute it. It seems that what is doing the work in Johnston's solution is not just the distinction between constitution and identity, but a tacit restriction on when there is a ‘higher-level’ object constituted by certain ‘lower-level’ objects. To that extent, his theory also resembles Markosian's brutal composition theory, though since Johnston can accept that every set of atoms has a fusion his theory has different costs and benefits to Markosian's theory.