The purpose of this article is to show that the ethics presented in Ricoeur's Oneself as Another can and must be thought in relation to the anthropology and ontology that the philosopher has gradually developed from the time of his first great phenomenological philosophical project through to his mature work. In order to outline this approach of relating the onto-anthropological foundations to Ricoeur's ethics, we start with Ricoeur's early texts where he develops a long meditation on the risk implied by the act of freedom: the risk of being oneself, of deciding and acting in the world with and for others. Then, our analysis focuses on the Ricoeurian conception of consent and affectivity to see the extent to which it is able to shed light on the development of ethics and the notion of the ethical subject in the context of the hermeneutical phenomenology of Ricoeur. The article thus takes us from an analysis of the question of "I can" and "I want" in Freedom and Nature: the Voluntary and the Involuntary, through Fallible Man to finally end with an examination of the "acting and suffering" human being found in Oneself as Another.