An obvious approach to developing a logic of goals or desires is to adapt possible worlds semantics - see, e.g., [Wooldridge, 1994][Cohen and Levesque, 1990a]. In this view, each goal-accessible world represents one way the world might be if the agent's goals were realised. However, this approach falls prey to the side effect problem, in that it predicts that agents have a goal of the logical consequences of their goals (cf. the logical omniscience problem, discussed above). This is not a desirable property: one might have a goal of going to the dentist, with the necessary consequence of suffering pain, without having a goal of suffering pain. The problem is discussed, (in the context of intentions), in [Bratman, 1990]. The basic possible worlds model has been adapted by some researchers in an attempt to overcome this problem [Wainer, 1994]. Other, related semantics for goals have been proposed [Rao and Georgeff, 1991b][Kiss and Reichgelt, 1992][Doyle et al., 1991].