Well, where's the nothing?
   If there's people, there's not nothing. If there's a wall,
   there's not nothing. If they're sitting there thinking and
   pondering something or feeling something, there's not nothing.
   It qualifies as performance art or perhaps as a not-shiny mirror
   reflecting back at the subject, turning the subject into the
   object of art that is being considered in the aesthetic.

   "My thoughts/feelings/emotions are the aesthetic now".

   That is the art in that style.. Nothing is a concept and thereby
   has properties. As soon as you name it and it's conceptualized,
   it becomes something with aesthetic interest. Even nothing is
   art.