Acts of Commanding and Changing Obligations

If we are to take the notion of speech act seriously, we must be able to treat speech acts as acts. In what follows, I will try to model changes brought about by various acts of commanding in terms of a variant of update logic. I will combine a multi-agent variant of the language of monadic deontic logic with a dynamic language to talk about the situations before and after the issuance of commands, and the commands that link those situations. Although the resulting logic inherits various inadequacies from monadic deontic logic, some interesting principles are captured and seen to be valid nonetheless. An outline of a proof of completeness and some interesting valid principles together with concrete examples will be presented.