Remembering is possible only on that of forgetting, and not vice versa

Just as expecting is possible only on the basis of awaiting, remembering is possible only on that of forgetting, and not vice versa; for in the mode of having-forgotten, one’s having been ‘discloses’ primarily the horizon into which a Dasein lost in the ‘superficiality’ of its object of concern, can bring itself by remembering. The awaiting whichforgets and makes present is an ecstatical unity in its own right, in accordance with which inauthentic understanding temporalizes itself with regard to its temporality. The unity of these ecstases closes off one’s authentic potentiality-for-Being, and is thus the existential condition for the possibility of irresoluteness. Though inauthentic concernful understanding determines itself in the light of making present the object of concern, the temporalizing of the understanding is performed primarily in the future.

—Martin Heidegger, Being and Time, H.339