 Sartre’s slogan—“existence precedes essence”—may serve to introduce what is most distinctive of existentialism, namely, the idea that no general, non-formal account of what it means to be human can be given, since that meaning is decided in and through existing itself. Existence is “self-making-in-a-situation” (Fackenheim 1961: 37). Webber (2018: 14) puts the point this way: “Classical existentialism is ... the theory that existence precedes essence,” that is, “there is no such thing as human nature” in an Aristotelian sense. A “person does not have an inbuilt set of values that they are inherently structured to pursue. Rather, the values that shape a person’s behavior result from the choices they have made” (2018: 4). In contrast to other entities, whose essential properties are fixed by the kind of entities they are, what is essential to a human being—what makes her who she is—is not fixed by her type but by what she makes of herself, who she  becomes.[6]  The fundamental contribution of existential thought lies in the idea that one’s identity is constituted neither by nature nor by culture, since to “exist” is precisely to constitute such an identity. It is in light of this idea that key existential notions such as facticity, transcendence (project), alienation, and authenticity must be understood.