On **Tuesday** (!!), **March 20**, at **3 p.m.**, Roberto Ciuni (Bochum) will give a talk at the LIRa seminar on **Ought Implies Can, Omission and Probabilistic Deliberative STIT**.

The talk will take place in Science Park 904, Room D1.113.

**Abstract:**

STIT logics are prominent formal settings for modelling the interaction among agents. Remarkably, they endorse some basic ideas of Game Theory, most notably that the moves of one agent are independent from the ones of any other agent. This is in turn reflected in the semantics of the stit operator [a], which reads `agent a ensures –´(where the hyphen stays for a proposition expressing an `outcome´). In the last ten years, STIT logics have been applied to a number of issues at the cross between deontic logic, ethics and legal philosophy, such as the notion of responsibility. The Principle of `Ought implies Can’ (OC) is a widespread principle in ethics, which is taken to provide a criterion of fairness for establishing `oughts´. Responsibility for omission is that kind of responsibility which holds of an agent if she did not ensure something she had the obligation of ensuring. Among the cases of omission, we have omission w.r.t. other agents’ wrong-doing (not preventing other from accomplishing violations of norms). In the paper, I show that responsibility for this kind of omission (RNP) is impossible in any STIT logic which endorses OC. Since there are reasons for keeping STIT, OC and RNP, I explore a way to fix the problem which does not renounce to any of them: I introduce a STIT logic which is able to deal with the notions of `attempting´ and `maximizing the chance that another agent fails´. Interestingly, this is done without renouncing to the `Independence of Agents´, which is indeed the principle that makes traditional STIT and Game Theory fail when modelling RNP. The new apparatus has then a real advantage not only w.r.t. to other logics of the STIT framework, but also w.r.t. to a widespread mathematical modal of agents’ interactions.