ABSTRACT
The version of standard deontic logic (SDL) semantics most appropriate for ought to do statements is probably Hintikka's semantics of deontic alternative worlds. For the semantics of ought to be statements, a version whose worlds are optimal or permissible is more plausible. Moreover, just as people found that optimal worlds had to be weakened to improved worlds and finally to relatively good worlds in order to give plausible truth-conditions for ought to be statements. As they usually understand them, so too permissible worlds can mean no more than relatively good worlds. The chief of these difficulties was that we have no way of specifying deontically accessible worlds without already knowing what persons ought to do in this world. They find no such outcome in the semantics of ought to be statements. The author concludes that SDL, whether taken as a logic of ought to be statements or as a logic of ought to do statements, is unsatisfactory.
