Body', '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 HeideggerSince time itself is not movement, it must somehow have to do with movement.Time is initially encountered in those entities which are changeable, change is in time. How is time exhibited in this way of encountering it, namely, as that within which things change? Does it here give itself as itself in what it is? Can an axplacation of time starts here guarantee that time will thereby provide as it were the fundamental phenomena that determine it in its own being?
Martin HeideggerWhy are there beings at all instead of nothing? That is the question. Presumably it is not arbitrary question, "Why are there beings at all instead of nothing"- this is obviously the first of all questions. Of course it is not the first question in the chronological sense [...] And yet, we are each touched once, maybe even every now and then, by the concealed power of this question, without properly grasping what is happening to us. In great despair, for example, when all weight tends to dwindle away from things and the sense of things grows dark, the question looms.
Martin Heidegger