 Our metaphysical calculations are subliminally influenced by how we picture possible worlds (Coggins 2010, chapter 3). If possible worlds are envisaged as containers, then they can be completely emptied. Similarly, if possible worlds are pictured as stories (say maximally consistent ways things could have been), then our library will contain a tale lacking any concrete entities as characters. But if possible worlds are pictured mereologically, as giant conglomerates of concrete objects (Lewis 1986), our subtraction falters before we reach zero. Similarly, if possible worlds require an active construction (say, imaginary rearrangements of objects drawn from the actual world), then the very process of construction ensures that there are some concrete objects in every possible world.