 Closely connected with inconsistent information is the issue of modelling inconsistent databases (see Barwise 1997). These may consist, for instance, in sets of data supplied by different sources which are inconsistent with each other, such as incompatible evidence presented by different witnesses in a trial. Intuitively, we are allowed to draw the logical consequences of data fed in by a single source, but should not conjoin data from distinct sources which may be inconsistent with each other. The data base is “compartimentalized”: occasional inconsistencies are placed in separate sectors and should not be asserted conjunctively (see e.g., Hyde 1997, Brown &amp; Priest 2004). Impossible worlds are useful in such models—particularly non-adjunctive worlds, where a conjunction may be false even if both conjuncts are true. (We discuss such worlds further in  section 5.2.)