In this paper we motivate and describe a dialogue manager which is able to infer and negotiate causal implicatures. A causal implicature is a type of Gricean relation implicature, and the ability to infer them is crucial in situated dialogue. Because situated dialogue interleaves conversational acts and physical acts, the dialogue manager needs to have a grasp on causal implicatures in order not only to decide what physical acts to do next but also to generate causally-aware clarifications.