Marek Sergot
In philosophical logic, much of the emphasis in the logic of action has been on agency, that is, on characterising how the actions of a particular agent, or group of agents, can be said to be the cause of, or responsible for, a certain outcome or state of affairs. The best known examples are probably the `stit' (seeing to it that) family of logics associated with Nuel Belnap and colleagues, though there are other examples, notably Ingmar P\"orn's logic of `brings it about'. I will sketch the elements of a formalism that combines a treatment of agency with a transition-based account of action more usually encountered in computer science and temporal logic. I will concentrate on presenting some simple examples rather than formal properties of the logic. The aim is to illustrate something of the expressive power and the appeal of these approaches to agency, but also to identify some of their weaknesses and inadequacies. All the examples involve an element of indeterminism, because of the environment---in some examples it might rain, in others a fragile object might or might not break when it falls---and because the possible actions of other agents have to be taken into account as well.