What does it mean to hide something on the stage? The theatre announces the importance of the visible in its very name, derived from theatron (‘seeing-place’), but the consummation of its effects also depend on what is invisible and implied. Shylock's baptism, for instance, never actually occurs in The Merchant of Venice. Nor does the banquet that distracts him so Jessica can be ferried away from her home. But these ‘scenes’ are essential to the play; they tissue the dramatic action with the vitality of actual occurrences. Likewise, an implied space behind a door or window can seem as real as the actual onstage world, as with the next room in which attempts to create the philosopher's stone lead to a literally explosive climax in Ben Jonson's Alchemist, or the intimate familial reconciliations in The Winter's Tale that the gentlemen witness and then report excitedly to each other, but which we never actually see. Andrew Sofer, drawing on the language of physics, terms these immaterial but powerful aspects of the theatre ‘dark matter’, the ‘invisible phenomena’ that ‘continually structure and focus an audience's theatrical experience’ and ‘remain incorporeal yet are crucial to the performed event’. Much like the dark matter that helps construct the universe, the dark matter of theatre is both vital and, by definition, unprovable in its existence.

And yet dark matter need not even occur offstage. One way of thinking about the theatre is that it plays with the very notion of presence in its construction of what is decidedly onstage. Much of the discipline of performance studies has focused on a fundamental tension within the theatrical event: to perform is to stand in and represent, as if in constitution of authority, but also to become ephemeral and fleeting. To perform is, in a sense, to promise disappearance, even as performance seems to insist on its capacity to draw attention and emulate reality. In Peggy Phelan's influential account, performance thus structures itself around its ‘unmarked’ elements, leaving its marked appearance fragile and fluctuating. Performance, Phelan attests, can only live ‘in the present. Performance cannot be saved, recorded, documented, or otherwise participate in the circulation of representations of representations: once it does so, it becomes something other than performance’.