What makes theatre? Why should anyone, voluntarily, opt to spend time sitting with a whole load of other strangers in a darkened room? Are we, who do it for pleasure, mad or what?

Last night, sitting in BAC's Studio 2 listening to Shelagh Stephenson's horror-struck radio play Five Kinds of Silence (first broadcast on Radio 4 two years ago) the question seemed even more pertinent. What was I doing? Didn't I have anything better to do than sit in darkness listening admittedly to a fine, though traumatising, account of three women being terrorised for half their lives by Tom Courtenay's disturbed father/husband such that, like Brookside's Beth Jordache, they were moved finally to shoot him down like an old, rabid dog?

The experience, part of BAC's Playing in the Dark season, goes perhaps to the heart of what ''theatre'' may have to offer at the butt end of the twentieth century.

In a spirit of inquiry that Peter Brook himself would surely applaud, over the next few weeks, Playing in the Dark will experiment, without any extraneous distractions, exactly what happens when you throw people into a pitch black room and ask them to listen/experience Shakespeare, poetry, comedy - even eating a meal.

So what did I ''learn'' from last night. Darkness's ''heaviness'', the fear absence of light brings up (okay any small child and indeed Stephenson's Billy, punished by being locked away as a child in a cupboard, could tell you that), spatial dislocation and how energy and expectation is all.

I ''heard'' the play less well than I might have done listening to Radio 4 in my own room; I was too distracted. On the other hand, I undoubtedly had ''an experience.''

Playing in the Dark continues into July.