The senses do not enable us to cognize any entity in its Being; they merely serve to announce the ways in which 'external' Things within-the-world are useful or harmful for human creatures encumbered with bodies....they tell us nothing about entities in their Being.
Martin HeideggerEveryone is the other, and no one is himself. The they, which supplies the answer to the who of everyday Da-sein, is the nobody to whom every Da-sein has always already surrendered itself, in its being-among-one-another.
Martin HeideggerProfound boredom, drifting here and there in the abysses of our existence like a muffling fog, removes all things and men and oneself along with it into a remarkable indifference. This boredom reveals being as a whole.
Martin HeideggerBody', 'soul', and 'spirit' may designate phenomenal domains which can be detached as themes for definite investigations; within certain limits their ontological indefiniteness may not be important. When, however, we come to the question of man's Being, this is not something we can simply compute by adding together those kinds of Being which body, soul, and spirit respectively possess--kinds of being whose nature has not as yet been determined. And even if we should attempt such an ontological procedure, some idea of the Being of the whole must be presupposed.
Martin Heidegger