This is a literal expression of the German phrase 'Da-Sein.'
It means roughly the same thing as the Canadian idiom 'How's it going?' where 'it' means oneself.
While the expression ‘being there’ is often used as a term of positive or negative judgment (‘he’s there for me’, ‘she’s never there for you when you really need her’), here it denotes one's very ordinary sense of existence.
It makes us reflect on our own capacity for self-support rather than the help we give and get in relating to others.
Peter Sellers' last great ironic political comedy about a witless man being made into the US President was appropriately called Being There.
