 Mirroring is manifest to the extent that features of the imaginary situation that have not been explicitly stipulated are derivable via features of their real-world analogues, or, more generally, to the extent that imaginative content is taken to be governed by the same sorts of restrictions that govern believed content. For example, in a widely-discussed experiment conducted by Alan Leslie (1994), children are asked to engage in an imaginary tea party. When an experimenter tips and “spills” one of the (empty) teacups, children consider the non-tipped cup to be “full” (in the context of the pretense) and the tipped cup to be “empty” (both within and outside of the context of the pretense). In fact, both make-believe games and more complicated engagements with the arts are governed by principles of generation, according to which prompts or props prescribe particular imaginings (Walton 1990).