Heidegger is important and occupies a pivotal role in this study because he provides the resources for a rich ontological understanding of responsibility for which ethics can be thought in terms of being and its event. It is in Heidegger that we find radically new conceptions of what being responsible means, such as the facticity of responsibility, the call of conscience and being-guilty, the assumption of finitude, an exposure to an inappropriable event, and so on. In short, we have an 'originary ethics' that is first and foremost a thinking of being and not a thinking of the subject in terms of the classical repertoire of concepts such as agency, will, and subjectivity. In Heidegger we find, as Raffoul puts it, the 'ethicality' of being itself in which being is to be conceived not as a substantial ground but as an event that calls for responsible engagement and praxis.
It is in these chapters that Raffoul carries out some of the most original work in the book, showing the extent to which Heidegger is indeed a major thinker of a renewed sense of responsibility. He locates this in the very structure or being of Dasein itself which, he maintains, needs to be understood as an 'archi-ethical' notion and in which ethical responsibility is thought in terms that are very different to the way it is conceived in the classical conception of a free, autonomous subject. Here responsibility is not conceived 'as imputability of the free subject, but is instead approached in terms of a response to an event that is also a call', such as the call of conscience. This means that there is a care of self in Heidegger, as one might put it, that is having to be true to oneself, but this is to be thought as a 'response' to a call within being itself and qua the 'event' of being.