86 I. 2
Being and Time

And even though Being-in-the-world is something of which one has pre-phenomenological experience and acquaintance [erfahren und gekannt], it becomes invisible if one interprets it in a way which is ontologically inappropriate. This state of Dasein's Being is now one with which one is just barely acquainted (and indeed as something obvious), with the stamp of an inappropriate interpretation. So in this way it becomes the 'evident' point of departure for problems of epistemology or the 'metaphysics of knowledge'. For what is more obvious than that a 'subject' is related to an 'Object' and vice versa? This 'subject-Object-relationship' must be presupposed. But while this presupposition is unimpeachable in its facticity, this makes it indeed a baleful one, if its ontological necessity and especially its ontological meaning are to be left in the dark.

Thus the phenomenon of Being-in has for the most part been represented exclusively by a single exemplar—knowing the world. This has not only been the case in epistemology; for even practical behaviour has been understood as behaviour which is 'non-theoretical' and 'a theoretical'. Because knowing has been given this priority, our understanding of its ownmost kind of Being gets led astray, and accordingly Being-in-the-world must be exhibited even more precisely with regard to knowing the world, and must itself be made visible as an existential 'modality' of Being-in.

¶ 13. A Founded Mode in which Being-in is Exemplified.1 Knowing the World.

If Being-in-the-world is a basic state of Dasein, and one in which Dasein operates not only in general but pre-eminently in the mode of everydayness, then it must also be something which has always been experienced ontically. It would be unintelligible for Being-in-the-world to remain [60] totally veiled from view, especially since Dasein has at its disposal an understanding of its own Being, no matter how indefinitely this understanding may function. But no sooner was the 'phenomenon of knowing the world' grasped than it got interpreted in a 'superficial', formal manner.

1 'Die Exemplifizierung des In-Seins an einem fundierten Modus.' The conception of 'founded' modes is taken from Husserl, who introduces the concept of 'founding' in his Logische Untersuchungen, vol. II, Part I, chapter 2 (second edition, Halle, 1913, p. 261). This passage has been closely paraphrased as follows by Marvin Farber in his The Foundation of Phenomenology, Cambridge, Massachusetts, 1943, p. 297; 'If in accordance with essential law an a can only exist in a comprehensive unity which connects it with a μ, then we say, an a as such needs foundation through a μ, or also, an a as such is in need of completion by means of a μ. If accordingly a0, μ0 are definite particular cases of the pure genera a, or μ, which stand in the cited relationship, and if they are members of one whole, then we say that a0 is founded by μ0; and it is exclusively founded by μ0 if the need of the completion of a0 is alone satisfied by μ0. This terminology can be applied to the species themselves; the equivocation is harmless.' Thus a founded mode of Being-in is simply a mode which can subsist only when connected with something else.

Being and Time (M&R) by Martin Heidegger