Towards a Formalization of Responsibility

In this paper we aim at formalizing two distinct notions of responsibility: backward-looking responsibility and forward-looking responsibility. The first notion implies blameworthiness while the second one implies obligation. They are related to each other though, since, under certain conditions, forward-looking implies backward-looking. We claim here that an ideal framework of cooperative agency should be able to express both notions and also capture this relation. We provide such a framework by using an extension of alternating-time temporal logic called CATL. It turns out that the possibility of explicitly use strategies in the object language of CATL provides a useful tool to attend our aim.