One cannot step twice into the same river, nor can one grasp any mortal substance in a stable condition, but it scatters and again gathers; it forms and dissolves, and approaches and departs—Heraclitus. Play is always play of absence and presence, but if one wishes to think it radically, one must think it before the alternative of presence and absence; it is necessary to think of Being as presence or absence from the possibility of play on, and not the other way around—Derrida.