GA25:19-20 – Human Dasein

Human Dasein is a being which has a world; or, to put it differently, the mode of being of Dasein, existence, is essentially determined by being-in-the-world. "World" is that particular whole toward which we comport ourselves at all times. The personal relation of one existence to another is also not a free floating cognitive relation of an I-self to a thou-self, as if they were isolated souls; but rather each is a factical self in a world, and the being of the self is essentially determined by its comportment to this world.
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Human Dasein which has a world is a being who is concerned with its own existence, indeed in such a way so as to choose itself or give itself over to choice. The existence which always makes up our being— though not the only determinant—is a matter of our freedom; and only a being which can be resolved and has resolved itself in such and such a way can have a world. World and freedom as basic determinations of human existence are most closely related.

For our purposes of interpreting the essence of science from out of the mode of being of Dasein (existence), these determinations of Dasein (being-in-the-world and freedom) are sufficient.

It is not difficult to arrive at further determinations from the one mentioned in the first place. Dasein exists: It is in a world within which it encounters beings and to which the existing Dasein comports itself. However, these innerworldly beings toward which Dasein comports itself are revealed in, through, and for this comportment. But at the same time the comporting Dasein is also revealed to itself; the one who exists, Dasein, is manifest to itself, without being the object of a penetrating self-observation. [PIKCPR:14-15]