In his effort to redefine man, Heidegger introduces a statement: ‘the ownmost of Dasein consists in its existence” (BT, 68). Let us first clarify what Heidegger means by existence. He had already said that what is unique to the being of man is that “in its very being its own being is an issue for it” (BT, 33). A cat doesn't concern itself with being a cat, a tree doesn't concern itself with being a tree, but persons do concern themselves with being certain kinds of persons (a builder, painter, woman, parent and so on). This is because, unlike cats or trees, we define our own being as we go along. We are continually faced with possibilities from among which we can choose and, at each choice, we actualize at least one of the possibilities available to us while closing off others in the process. This grasping of only some possibilities defines us as one kind of self rather than another: a dishonest choice defines us as dishonest, fixing broken windows defines us as a glazier, and so on. We have to carry out these choices daily; being brave last week for instance does not mean that you are being brave today. Therefore, living the life of a person is a matter of constantly (a) taking a stand on who we are and (b) being defined as who we are by taking that stand (no choice is 'once and for always' so we have to keep on choosing to be who we are). Added to this, the being of everything else on the planet is also an issue for us because we deal with things as what they are and persons as who they are. Only persons, for example, deal with spades as spades or cards as cards (i.e., we relate to them as meaningful and as fitting meaningfully into and with other things and/or activities). Only that being that is in the manner of existence can encounter another entity in its instrumental character as a spade or a playing card.