It lies at the core of us, and of much great art. There are few more profound questions than Who Am I, and What Am I, after all.
The answers are often not set in stone. Your own view of your identity may be fluid. Your own view of your individual identity may be different from other people's view of yours. As we found with Alasdair Gray's controversial categories of English "colonists and settlers", labels and stereotypes tend to not only obscure key differences between virtually everyone, but also incite argument and rancour.
They are the first announced shows from an ambitious first season for the National Theatre of Scotland's new artistic director Laurie Sansom.
In a large touring show, The Great Don't Know Show, two leading writers and directors, David Greig and David MacLennan, will curate a series of scenes, songs, skits, rants and dramas which will take both sides of the referendum debate and all points inbetween.
Acclaimed Scottish playwright Greig, whose version of Charlie and the Chocolate Factory opened in London this week, is in the Yes camp.