Art?

Human beings have been making art for millenia upon millenia. It comes in almost unlimited shapes and forms and media. It speaks to everything we do and think and dream. It represents the person and the culture in its present and its future existence.

But in all of its diversity and functions, what makes all of it art? What is the common element? Is it in its substance, its mystery, its transformative power, its function as a mirror, its role in culture? Is it like John Paul Stephens' description of pornography: I can't define it but I know it when I see it.

Is it simply a language beyond words?