can be proved, makes no sense if it is raised by Dasein as Being-in-the-world; and who else would raise it? Furthermore, it is encumbered with a double signification. The world as the "wherein" [das Worin] of Being-in, [203] and the 'world' as entities within-the-world (that in which [das Wobei] one is concernfully absorbed) either have been confused or are not distinguished at all. But the world is disclosed essentially along with the Being of Dasein ; with the disclosedness of the world, the 'world' has in each case been discovered too. Of course entities within-the-world in the sense of the Real as merely present-at-hand, are the very things that can remain concealed. But even the Real can be discovered only on the basis of a world which has already been disclosed. And only on this basis can anything Real still remain hidden. The question of the 'Reality' of the 'external world' gets raised without any previous clarification of the phenomenon of the world as such. Factically, the 'problem of the external world' is constantly oriented with regard to entities within-the-world (Things and Objects). So these discussions drift along into a problematic which it is almost impossible to disentangle ontologically.
Kant's 'Refutation of Idealism'ix shows how intricate these questions are and how what one wants to prove gets muddled with what one does prove and with the means whereby the proof is carried out. Kant calls it 'a scandal of philosophy and of human reason in general'x that there is still no cogent proof for the 'Dasein of Things outside of us' which will do away with any scepticism. He proposes such a proof himself, and indeed he does so to provide grounds for his 'theorem' that 'The mere consciousness of my own Dasein-a consciousness which, however, is empirical in character—proves the Dasein of objects in the space outside of me,'xi
We must in the first instance note explicitly that Kant uses the term 'Dasein' to designate that kind of Being which in the present investigation we have called 'presence-at-hand'. 'Consciousness of my Dasein' means for Kant a consciousness of my Being-present-at-hand in the sense of Descartes. When Kant uses the term 'Dasein' he has in mind the Being-present-at-hand of consciousness just as much as the Being-present-at-hand of Things.
The proof for the 'Dasein of Things outside of me' is supported by the fact that both change and performance belong, with equal primordiality, to the essence of time. My own Being-present-at-hand—that is, the Being-present-at-hand of a multiplicity of representations, which has been given in the inner sense—is a process of change which is present-at-hand. To have a determinate temporal character [Zeitbestimmtheit], however, presupposes something present-at-hand which is permanent. But this cannot be 'in us', 'for only through what is thus permanent can my