 Recall from section 2.1.1 that a fundamental problem with the classical semantic theories of Hamblin (1973) and Karttunen (1977) is that they do not specify clear criteria for when a response should count as a “possible answer”. Partition semantics (Groenendijk and Stokhof 1984) does specify explicitly which responses should count as possible answers, namely only those that are true and exhaustive. In many cases, it is clear what the true and exhaustive responses to a given question are. However, this is not always the case, as witnessed by conditional and alternative questions. A natural way to proceed, then, is to consider another criterion for what should count as a possible answer.