Our Chosen Field

It's a simple enough question: one that should be asked often when in pursuit of a goal, but the frequency of discussions never delve deeper than 440hz (Music nerd humor). I want to get to the very depths of, not only my own understanding, but yours and I know no group better qualified than you my friends. So I ask you, what is theater best at? What can theater do that no other art form can? That nothing else can? What makes it special in general and to you?