Elie During (University of Paris 10 Nanterre) has written extensively on metaphysics, Bergson, Whitehead, French theory in America, scientific epistemology - to name justa few topics - and he is a series editor along with Quentin Meillassoux of PUF's 'MetaphysiqueS' series. This talk, delivered at the European Graduate School, discusses "floating time" as coexistence, Bergson, community, Deleuze, Serres, and the metaphysics of the twin paradox.