 Note that the problem of impossible fictions affects Walton’s make-believe account rather differently.  Truth in fiction for Walton is a function of prescriptions to imagine, and he is relatively sanguine about such prescriptions in the case of impossible fictions. Even contradictions, he suspects, can be imagined in the relevant sense, but he adds that even if they can’t, his account of fictionality or fictional truth is safe.  He offers two options: first, there might be prescriptions to imagine a contradiction even if actually imagining it is not possible; secondly, there might be separate prescriptions to imagine p and not-p, but not their conjunction (Walton 1990, 64–6).