Are there theories that try to explain theatre?
There are many theories to do with theatrical output. These go back to its earliest days. Aristotle came up with one of the first which broke theatre down into six distinct elements ranging from plot to spectacle. Famous theatrical theorists in the modern age include Bertolt Brecht, who rejected many Aristotelian ideas, and Dario Fo, an Italian playwright who championed improvisation as a theatrical art form.