When an agent “loses herself” in a project, or becomes completely absorbed in an activity, she has what Heidegger calls “reflected self-understanding”. This kind of reflected understanding allows the agent to find herself out in the world, “in things”, without ever holding any reflexive attitudes about herself. In my dissertation, I develop and defend Heidegger’s account of reflected self-understanding, which constitutes – for Heidegger – the most basic grip an agent has on who she is. I suggest that Heidegger’s account of reflected self-understanding is not only a significant contribution to the history of philosophy, but also the central kernel that structures Heidegger’s thought on the topics of understanding, interpretation, truth, and authenticity in Being and Time.

When thinking about the good life, we probably first think of things like a comfortable home, a satisfying career, meaningful relationships, good food, and involvement in worthwhile causes like reducing world hunger or improving education. But literature and life are replete with individuals who have these things but still find their life lacking. Tolstoy’s crisis recounted in Confession, for example, arose in the midst of a flourishing estate, recognized masterpieces, and a provided-for family. The supposed elements of a rich and satisfying life still lacked the meaning he had hoped for. On reflection, then, the good life involves more than a checklist of desirable things and activities. We don’t just want meaningful relationships and successful careers. We want something more. But what exactly is this elusive extra? Often, people describe it as our desire to live lives that are truly our own or, more technically put, to live autonomous and/or authentic lives.

In this dissertation, I examine autonomy and authenticity as ways of explaining how an action or a life could be an agent’s own. On my account, autonomy and authenticity both depend on one’s practical identity. Autonomy is a matter of acting in conformity with one’s practical identity and authenticity is a matter of the agent taking ownership and responsibility for her practical identity. After developing accounts of autonomy and authenticity, I examine two further questions. I first examine how autonomy and authenticity can come into conflict in an individual. For example, how can living autonomously threaten an agent’s ability to live an authentic life? And, second, I examine the relationship between a self-conception and a practical identity and their effect on an agent’s ability to live an autonomous and/or authentic life.

I suggest that both autonomy and authenticity highlight important aspects of a rich human life. And if we ignore either, it will be to our conceptual peril, holding us back from a fuller understanding of the ways our lives can be (or, conversely, can fail to be) our own.

Most people think it is a good thing to be authentic—that is, to be oneself, to be true to oneself, or to express oneself in action. Yet the fact that we regard being authentic as an achievement means that we tend to fail to be ourselves in acting. This raises two related questions for philosophers: Why think that we should be authentic in what we do? And, if we think we should, why are we so often led astray from this ideal? This dissertation looks to the account of human agency contained in Martin Heidegger’s Being and Time to reconstruct his argument for why we should be authentic. This reconstruction takes its bearings from Heidegger’s appropriation of Aristotelian and Kantian models of action and agency, as well as from views in the philosophy of action known today as “constitutivism,” which hold that we can explain the authority of certain normative demands on us by appeal to the nature of action or agency. Heidegger’s version of constitutivism is unique is its attempt to show that, in virtue of acting at all, one is already committed not only to a standard of success in acting, but also to conditions that undermine success in acting. The first half of this work lays out Heidegger’s account of action and his distinctive conception of practical deliberation, which leads to a reconstruction of his account of our essential tendency to act inauthentically. The second half places his discussion of authenticity in relation to his philosophical methodology and his ontology, in order to find the resources to reconstruct his argument for why authenticity is an ideal of agency to which we are committed in virtue of acting at all. Ultimately, this reconstruction of Heidegger’s arguments in Being and Time offers a compelling, unified account of human agency that explains both why we should be authentic and why we so often fail to live up to this ideal.