Felicity conditions for requests
* Propositional content condition: the requested act is a future act of the hearer
* Preparatory precondition: 1) the speaker believes the hearer can perform the requested act; 2) it is not obvious that the hearer would perform the requested act without being asked
* Sincerity condition: the speaker genuinely wants the hearer to perform the requested act
* Essential condition: the utterance counts as an attempt by the speaker to have the hearer do an act
