It is a constant frustration to me that I will never experience the first performance of Oedipus Rex. I will never know what it feels like to gather in the Theater of Dionysus with my entire city and watch an ancient king sacrifice himself for his people, with the civic structures and rocky landscape of my homeland sprawling out from all sides of the open stage. I will never stand among the groundlings of Shakespeare’s Globe, smelling the roasted nuts or feeling a pickpocket slit my purse strings as I hear the words “To be or not to be.” I will never gasp in shock at the chorus of crickets that Stanislavsky, to Chekhov’s horror, piped into the Moscow Art Theater for the first production of The Seagull. Every time I step into the classroom to teach these great dramatic texts, I am reminded of what insufficient evidence they are of the ephemeral live events they first proposed.

Plays are not like other forms of literature. I can pick up my tattered copy of The Great Gatsby, brew up a mug of tea, curl up in my favorite chair, and have something close to the experience that Fitzgerald originally imagined when he wrote the text: an individual encountering words on a page. The work was meant to be read.

Aristotle tells us that a great tragedy can achieve its effect without the benefit of public performance or actors, but I am not so sure. In the theater, our tools are space and time. The spoken word is just one way we shape these media. An important tool, no doubt. Perhaps the most enduring. But a performance also shapes space and time with the actors’ bodies, with gesture, with costume, and with music. Its contours are affected by the time of day, the arrangement of the theater space, the unique individuals who are gathered in the audience, and its relationship to the space and time outside the theater. A play operates on the full bodies and lives of its audience. It springs into being anew with each performance, and it takes the shape of the culture that creates it.

“An actor without insight into the history and context of the art form is limited, an incomplete artist whose work is ultimately diminished.”

A study of theater history is full of uncertain evidence. Even the things known about something like Greek Tragedy are, at best, an educated guess, cobbled together from fragmentary allusions in history, philosophy, and the visual arts. And the list of things we think we know is dwarfed by what we know we never will—melodies that were never noted down, movement that defied description, countless performances that were never recorded in written form or whose manuscripts have been lost to time.

But if I were deterred by the prospect of never-knowing, then I would not be in the theater. For all their uncertainties, the dramatic texts that have survived are great texts, full of vivid clues to these lost moments in space and time. For any serious actor, learning to listen to these clues is a skill just as important as technique and craft—this takes practice, presence, and a vast imagination. An actor without insight into the history and context of the art form is limited, an incomplete artist whose work is ultimately diminished. Without the certainty to know, we are left with the freedom to imagine, and this is where great theater begins.

Elliot B. Quick teaches theater history classes for actors at the Maggie Flanigan studio in New York, NY.