The philosophical movement known as Existential Philosophy, or existentialism, to which authors such as Søren Kierkegaard, Martin Heidegger, and Jean-Paul Sartre made significant contributions, has developed a distinctive philosophy of anxiety. It focuses on inwardness, the reflective self-relation of the individual, and the responsibility for one’s own actions. It emphasizes that, taken to its radical conclusion, there is nothing external that could ground, justify, or excuse one’s decisions, so that freedom and responsibility become an inner burden and are profoundly accompanied by anxiety. In order to clarify this dimension, existential philosophy introduces the conceptual distinction between essential anxiety [Angst] and everyday fear. Later authors such as Günther Anders and Hans Jonas also build on these theories of anxiety. They call for heightened awareness of the new threats of the twentieth century through a willingness to anxiety.