Abstract: This article reports on an investigation into an alternative semantics for actions which is based on modal logic, with an underlying computational theme, where actions are interpreted as computations in an abstract machine model of the world. The frame problem is addressed by reformulating and generalising minimal change principles to the principle of 'Occam's razor'-the intended interpretation of an action is given by the simplest computations which realise its direct effects. ?? 2008 Springer Berlin Heidelberg.
