Heisenberg's proposition about an objective real world not exisiting until observed, was given long ago in the Yoga Vashishtha, a book attributed to Valmiki who wrote there what the yogi Vashistha taught. 

In my view it only means that for a specific person, the world which that person is unware of, may well not exist as that person is preoccupied with some other real or imagined environment, and is not aware of being affected or being experienced in reference to that unknown world.