The first and only person who has gone any stretch of the way towards investigating the dimension of Temporality or has even let himself be drawn hither by the coercion of the phenomena themselves is Kant. Only when we have established the problematic of Temporality, can we succeed in casting light on the obscurity of his doctrine of the schematism. But this will also show us why this area is one which had to remain closed off to him in its real dimensions and its central ontological function. Kant himself was aware that he was venturing into an area of obscurity: 'This schematism of our understanding as regards appearances and their mere form is an art hidden in the depths of the human soul, the true devices of which are hardly ever to be divined from Nature and laid uncovered before our eyes.' Here Kant shrinks back, as it were, in the face of something which must be brought to light as a theme and a principle if the expression "Being" is to have any demonstrable meaning. In the end, those very phenomena which will be exhibited under the heading of 'Temporality' in our analysis, are precisely those most covert judgments of the 'common reason' for which Kant says it is the 'business of philosophers' to provide an analytic.
In pursuing this task of destruction with the problematic of Temporality as our clue, we shall try to Interpret the chapter on the schematism and the Kantian doctrine of time, taking that chapter as our point of departure.  At the same time we shall show why Kant could never achieve an insight into the problematic of Temporality. There were two things that stood in his way: in the first place, he altogether neglected the problem of Being; and, in connection with this, he failed to provide an ontology with Dasein as its theme or (to put this in Kantian language) to give a preliminary ontological analytic of the subjectivity of the subject. Instead of this, Kant took over Descartes' position quite dogmatically, notwithstanding all the essential respects in which he had gone beyond him. Furthermore, in spite of the fact that he was bringing the phenomenon of time back into the subject again, his analysis of it remained oriented towards the traditional way in which time had been ordinarily understood; in the long run this kept him from working out the phenomenon of a 'transcendental determination of time' in its own structure and function. Because of this double effect of tradition the decisive connection between time and the 'I think' was shrouded in utter darkness; it did not even become a problem.