never something still outstanding as not yet present-at-hand, but which, as something which is essentially never present-at-hand, 'is' with the Being of Dasein, jn the sense of existence. Dasein is such that in every case it has understood (or alternatively, not understood) that it is to be thus or thus. As such understanding it 'knows' what it is capable of-that is, what its potentiality-for-Being is capable of.1 This 'knowing' does not first arise from an immanent self-perception, but belongs to the Being of the "there", which is essentially understanding. And only because Dasein, in understanding, is its "there", can it go astray and fail to recognize itself. And in so far as understanding is accompanied by state-of-mind and as such is existentially surrendered to thrownness, Dasein has in every case already gone astray and failed to recognize itself. In its potentiality-for-Being it is therefore delivered over to the possibility of first finding itself again in its possibilities.
Understanding is the existential Being of Dasein' s own potentiality-for-Being; and it is so in such a way that this Being discloses in itself what its Being is capable of .2 We must grasp the structure of this existentiale more precisely.
As a disclosure, understanding always pertains to the whole basic state of Being-in-the-world. As a potentiality-for-Being, any Being-in is a potentiality-for-Being-in-the-world. Not only is the world, qua world, disclosed as possible significance, but when that which is within-the-world is itself freed, this entity is freed for its own possibilities. That which is ready-to-hand is discovered as such in its serviceability, its usability, and its detrimentality. The totality of involvements is revealed as the categorial whole of a possible interconnection of the ready-to-hand. But even the  'unity' of the manifold present-at-hand, of Nature, can be discovered only if a possibility of it has been disclosed. Is it accidental that the question about the Being of Nature aims at the 'conditions of its possibility'? On what is such an inquiry based? When confronted with this inquiry, we cannot leave aside the question: why are entities which are not of the character of Dasein understood in their Being, if they are disclosed in accordance with the conditions of their possibility? Kant presupposes something of the sort, perhaps rightly. But this presupposition itself is something that cannot be left without demonstrating how it is justified.
We have, after all, already come up against this primordial understanding in our previous investigations, though we did not allow it to be included explicitly in the theme under discussion. To say that in existing, Dasein is its "there", is equivalent to saying that the world is 'there'; its Being-there is Being-in. And the latter is likewise 'there', as that for the sake of which Dasein is. In the "for-the-sake-of-which", existing Being-in-the-world is disclosed as such, and this disclosedness we have called "understanding". vii In the understanding of the "for-the-sake-of-which", the significance which is grounded therein, is disclosed along with it. The disclosedness of understanding, as the disclosedness of the "for-the-sake-of-which" and of significance equiprimordially, pertains to the entirety of Being-in-the-world. Significance is that on the basis of which the world is disclosed as such. To say that the "for-the-sake-of-which" and significance are both disclosed in Dasein, means that Dasein is that entity which, as Being-in-the-world, is an issue for itself.
1 'Ais solches Verstehen "weiss" es, woran es mit ihm selbst, das heisst seinem Seinkönnen ist.'
2 '... so zwar, dass dieses Sein an ihm selbst das Woran des mit ihm selbst Seins erschliesst.'