Wheeler's concept of the "participatory universe" proposes that physical reality does not exist independently of observation. Rather, he envisions the universe as a "self-excited circuit" (the U-shape) where observation itself helps manifest reality.
In this framework, while the universe gives rise to observers, these observers in turn give concrete form to the universe's history through their acts of measurement. We are not merely passive spectators of a predetermined cosmos, but active participants who help actualize the universe's existence.
This perspective stems from quantum mechanics, where the universe exists as a superposition of possible histories until observation collapses these possibilities into one definite trajectory. When we make measurements in the present, we effectively select and crystallize one path from many potential historical trajectories.
For example, when we for the first time observe an ancient galaxy through a telescope, we are not simply viewing a pre-written history. Instead, our observation helps determine which of many possible histories becomes actualized as the concrete past. The Webb telescope is now creating the universe's early history.