A debate between a media archaeologist/philosopher and a female journalist/writer about the nuclear disaster at Chernobyl. Not only a material accident, but a tragedy about human knowledge because people are still unable to understand the fatal nature of the catastrophe. Film presentation (DVD) in V2_.Unknown Quantity features the staging of two conversations between Paul Virilio and Svetlana Alexievich.Paul Virilio is a media-archaeologist and philosopher, author of many world renowned essays. Svetlana Alexievich is a Russian journalist and author of award-winning book Voices from Chernobyl: Chronicle of the Future. Her book is a stirring account of life after the accident, written from the hundreds of interviews she made with the witnesses and victims of the tragedy. For both of them, Chernobyl is not just an accident of substance, it is also an accident of knowledge, in the sense that man cannot even perceive the deadly nature of the event.Andrei Ujica quite consciously chose to use DVD-format for this film and has developed his first cinematographic construct intended not for projection onto a screen but for display on a monitor, which incidentally is itself a part of the game.The only intentional allusion from the history of cinema is to Tarkovsky's Stalker. The viewer is gradually brought to realize that Svetlana Alexievich is in fact a stalker by profession. She has come from the dead zone to pay a visit to Virilio in a public library. And what is Virilio himself, if not a stalker who fled to the big city many years ago?The presentation at the International Film Festival Rotterdam is the purely filmic version of Unknown Quantity and at the same time the final stage of this project. Its forerunner, a filmic installation with the same title was realized for Ce qui arrive, an exhibition conceived by Paul Virilio and held at the Fondation Cartier pour l'art contemporain in Paris (2002/03).