What makes the performing arts so special? While loosely, one might apply the term to any sort of presentation before an audience, critics have historically used the label to separate dance, music, and theater performance from the “static” visual arts. A painter, writer, or photographer can effectively transmit their work and their messages through time and even across significant cultural or linguistic barriers-preserving a moment, a vision, or an idea in a permanent medium. We get perhaps as close as we can to time traveling by looking at a Stieglitz photograph, some lines of Dante, or a cave-painting on an ancient wall, able to see (at least almost) the same thing that the creator did at the moment of inception or execution.The performing arts, on the other hand, are time-limited. We can’t ever really know what a Shakespeare play was like for the audience, aside from a few well-preserved accounts, and are instead left confronting his plays more as a part of literary history than theater. Nor can we ever know what it might have been like to have witnessed the first performance of Swan Lake at the Bolshoi Theater in 1895. Part of the magic is how they serve as a sort of event or spectacle, a one-of-a-kind occurrence that, even in the age of HD digital recording, can still only exist in full in the memory of those who were there to see it happen.Especially over the course of the twentieth century, the performing arts have been host to a few particularly significant developments. At the peak of artistic exploration in the post-war period, dancers, playwrights, and musicians used their mediums to respond to a growing need for new forms-the idea that the changing conditions of the world demanded a different sort of art than what had come before. While this drive could be identified in the visual arts as well, it was on stage that the artist could directly confront their audiences with a new way of thinking about things. Here are three key innovators any theater-goer should know about.Antonin Artuad: A writer, critic, and playwright inspired by the existential writings of Friedrich Nietzsche and Jacques Derrida, Artuad believed that theater for the 21st century must incorporate a sense of life’s harshness in a way that Romantic and Modern forms had been unable to. Emphasizing an embrace of chaos in the face of nihilism and a cross-cultural engagement with a diverse variety of traditional forms, Artuad’s insistence on breaking free of the limits of language and into the unexplored spaces of gesture and sound had a lasting impact on generations of dramatists and performers to come.Merce Cunningham: While Artuad turned to philosophy and Eastern cultures for inspiration, this dancer and choreographer incorporated elements of chance as a way of embracing the organic chaos of the creative process, incorporating random choices into the compositional process. While some of the outcomes might not be artistically serviceable, incorporating this aleatory element opened the artist up to new & surprising possibilities. Later in life, Cunningham continued to push the limits of the performing arts medium by experimenting with film and motion capture technologies, finding new ways to document and archive these former one-of-a-kind experiences.John Cage: Cunningham’s lifelong partner, Cage applied the variable aspects of chance to his musical performances, inspired by the ancient Chinese text I Ching, a divination manual known in the West as the Book of Changes. By consulting the patterns and sequences of the manuscript, Cage sought not so much to bring an order to what he saw as the chaos of life, but rather a redirection of attention; an awareness of the natural state of existence. While Cage may be best known for his composition 4’33”-four minutes and thirty-three seconds of silence from a performer sitting at a piano, the performing arts have enjoyed a lasting contribution from his work with unusual instrumentation and innovative use of new recording technology.