Heidegger holds that his investigation of the animal still succeeds in clarifying Dasein’s disclosing (which he calls ‘world-forming’), since it reveals that ‘[t]he manifestness of entities as such, of entities as entities, belongs to world’ (FCM: 274/GA29/30: 397). This is an important positive result. But notice that what the investigation has failed to do is to grasp the animal’s lēthē as wholly other than Dasein’s disclosing. So too, angst and alētheia fail to grasp what is wholly other than themselves. This does not mean that they do not grasp themselves at all, or that Heidegger’s investigation has failed. But it does mean that disclosing remains in some respect concealed. For, to understand something completely requires grasping that thing in light of the alterity of a contrast case or alternative. You have to grasp what something is not in order to wholly grasp what it is. Heidegger relies on this in his lectures on Hölderlin’s ‘Ister’, where he riffs on the idea that ‘[c]oming to be at home is [. . .] a passage through the foreign’ (HI: 49/GA53: 60). The idea is that you can only ever truly understand what is your own through an encounter with what is other. If disclosing cannot grasp its alternative in lēthē, then there is a sense in which it remains concealed from itself. Something of it is inaccessible—although precisely what is difficult to express. It is not that there is some portion or aspect of disclosing that is hidden, such that disclosing is partially manifest to itself and partially concealed from itself. It is not that something that belongs to it but is yet distinct from it is obscure, as was the case with the concealed ground of disclosing. It is rather that disclosing will in some sense forever exceed its own range because it cannot make sense of its own other without destroying the alterity of that other. This is what I meant by saying that disclosing is ultimately concealed.

The whither of thrownness is concealed when disclosing tries to grasp itself in its rather than. It always fails and so is concealed from itself. This is a form of kruptesthai: simultaneous self-concealing. Not everything is concealed in it—and in fact, its self-concealing is always manifest to disclosing in its very surprise at itself. As we saw in angst, the attempt to grasp the nothing in its alterity rebounds and reveals instead the surprising fact that disclosing is, rather than nothing. Angst turns into wonder.