German for “being-there”, Dasein is Heidegger’s word for the kind of being that we are: the being for whom its own existence is an issue. Instead of starting with a detached mind observing objects, Heidegger begins with us already thrown into a world - using tools, caring about things, living among others and facing our own finitude. Most of the time we drift along with the anonymous “they” (das Man), doing what one does. Authentic existence means owning our possibilities in the light of our mortality. One word on a T-shirt; one of the most influential ideas of twentieth-century thought.