 Heidegger’s critical reconsideration of Husserl’s phenomenology is guided not by epistemological concerns, but, instead, fundamental ontological ones. Heidegger agrees with Husserl that modern science has failed to account for the grounds on which it relies, and he also turns to phenomenology in order to bring these grounds into focus. Yet, Heidegger believes that phenomenology concerns an origin much deeper than consciousness, the transcendental ego, and its eidetic structures. For him, phenomenology contributes to ontology, first of all, by bringing into focus the being, or, ontological structures, that comprise human existence itself. For the early Heidegger, these structures involve what he calls ‘facticity.’ By this, he does not mean that human existence is a fact. Rather, he means that the ontological structures that comprise human existence are found not in consciousness, but, instead, in our being in the world—or, as he determines this terminologically, being-in-the-world (in-der-Welt-sein) (Heidegger, Being and Time, § 12 ff.). Thus, our attempts to understand ourselves (or, for that matter, to understand anything else) remain bound by structures of being in the world. Specifically, our attempts to understand ourselves (or anything else) remain conditioned by pre-structures that determine in advance which possibilities of a situation we find significant, and by moods that determine in advance our attunement to a situation we are “thrown” into, that is, a situation that affects us even though we have not chosen to be in it (Heidegger, Being and Time, §§ 28–34).