 Are there any logical principles which impossible worlds must obey? More precisely, is there any logical inference such that, for any (impossible) world \(w\), if the premises are all true according to \(w\), then so is the conclusion? There is at least one such inference: the trivial inference from \(A\) to \(A\). (For if \(A\) is true at world \(w\), then \(A\) is true at world \(w\)!) Are there any others? This is the granularity issue.