85 I. 2
Being and Time

Ontically as well as ontologically, the priority belongs to Being-in-the world as concern. In the analytic of Dasein this structure undergoes a basic Interpretation.

But have we not confined ourselves to negative assertions in all our attempts to determine the nature of this state of Being? Though this Being-in is supposedly so fundamental, we always keep hearing about what it is not. Yes indeed. But there is nothing accidental about our characterizing it predominantly in so negative a manner. In doing so we have rather made known what is peculiar to this phenomenon, and our characterization is therefore positive in a genuine sense—a sense appropriate to the phenomenon itself. When Being-in-the-world is exhibited phenomenologically, disguises and concealments are rejected because this phenomenon itself always gets 'seen' in a certain way in every Dasein. And it thus gets 'seen' because it makes up a basic state of Dasein, and in every case is already disclosed for Dasein's understanding of Being, and disclosed along with that Being itself. But for the most part this phenomenon has been explained in a way which is basically wrong, or interpreted in an ontologically inadequate manner. On the other hand, this 'seeing in a certain way and yet for the most part wrongly explaining' is itself based upon nothing else than this very state of Dasein's Being, which is such that Dasein itself—and this means also its Being-in-the world—gets its ontological understanding of itself in the first instance from those entities which it itself is not but which it encounters 'within' its world, and from the Being which they possess.

Both in Dasein and for it, this state of Being is always in some way familiar [bekannt]. Now if it is also to become known [erkannt], the knowing which such a task explicitly implies takes itself (as a knowing of [59] the world [Welterkennen]) as the chief exemplification of the 'soul's' relationship to the world. Knowing the world (νοεῖν)—or rather addressing oneself to the 'world' and discussing it (λόγος)—thus functions as the primary mode of Being-in-the-world, even though Being-in-the-world does not as such get conceived. But because this structure of Being remains ontologically inaccessible, yet is experienced ontically as a 'relationship' between one entity (the world) and another (the soul), and because one proximally understands Being by taking entities as entities within-the-world for one's ontological foothold, one tries to conceive the relationship between world and soul as grounded in these two entities themselves and in the meaning of their Being—namely, to conceive it as Being-present-at-hand.

Being and Time (M&R) by Martin Heidegger