I enter a large hall with three big tables. The room is lit in a warm, purple-tinted light that makes it seem like a party space. An expansive web of strings stretches across the entire space with little pieces of notepaper hanging at approximately eye level. Each table has around ten spaces to sit at. The individual space is set up with an old-fashioned analogue push-button telephone keypad, attached to a pair of headphones instead of a telephone receiver. The tabletops are covered in a psychedelic blackand-white wave pattern – like soundwaves or, at a stretch, an avant-garde tablecloth from the 1970s. This is apt, because I have entered what could be called a sound bar for philosophers. Next to each phone is a small wooden toolbox that accompanies me through the evening (see Figure 28.1): a set of different coloured pens for notetaking, paper clips, notepaper, dextrose goodies as brain food, and a set of Gedankenzettel (literally, notes for thought), some of which already have evocative images on them (a keyhole, for example). I find a seat, put the headphones on and start listening.

This is the setting of Philosophiermaschine (The Philosophising Machine), which opened in January 2020 at one of Berlin's major independent performance spaces, the Sophiensaele, and was conceived by the German performance collective Interrobang. Interrobang was founded in 2011 by co-artistic directors Nina Tecklenburg and Tillmann Muller-Klug, and its performances explore the underlying structures of contemporary society by developing participatory performance formats and theatrical installations that combine ‘game, fiction and narration […] as a means of emphatic questioning – as an interrobang’. In doing so, Tecklenburg and Muller-Klug prominently explore analogue and digital technologies as an interface for their theatre games and draw repeatedly on the history of radio drama with aurally based formats: Callcenter Übermorgen (2013) has participants enter into phone booths; The Müllermatrix (2016) brings GDR playwright Heiner Muller back to life in an elaborate audio installation; and most recently, Deep Godot (2021) offers a one-on-one conversation with an AI that is auditioning to become one's caregiver in later life. Die Philosophiermaschine combines many of these aspects.