If the ego (i.e., consciousness) does not, cannot, posit itself, as Nietzsche argues, can Existentialism be considered a type of philosophy, or even a philosophy at all? Put another way: is Existentialism best understood as a "sensibility" - an "existential sensibility," if you will - rather than a type of philosophy (e.g. Empiricism)? When we speak of "Being-for-itself" as opposed to "being-in-itself," are we referring to anything at all - that is to say, things which can actually be known? I ask this as an Existentialist (whatever that is, exactly).