  Morgenstern’s two chief criticisms of the causal approach to reasoning about actions are that it does not give an adequate account of explanation[34]  and that the logical context in which it works (the Situation Calculus) is limited. As work on the approach continues, progress is being made in these areas. But the constraints that a successful logic of action and change must meet are so complex that it seems to be a reasonable research methodology to concentrate initially on a restricted logical setting.