The theme is the central topic of something. The notion that a piece has to have a theme and be about something was put into question during the first half of the 20th Century by postmodern art, including dance, music and theater. With this break, artists compose work which is open enough to invite the audience to make their own meaning or they avoid it completely and compose according to purely formal methodologies. In this way, a piece is no longer a medium encoding a message, but an experience in itself. Just perceiving something as opposed to conceptualizing it, analyzing it, evaluating it or making sense of it is more difficult than it may seem. We can also call it being witness. Or meditation, which has been around far longer than postmodernism.