How would the room you are in be different, if you were not there?
This is like the thing about the light in the fridge going off when you close the door. Or, if no one is there to hear it, does a tree still make a noise when it falls in the forest. The whole thing about not being there bugs me. If I am not there, how are things different? If I miss my bus one morning, is the bus ride as uneventful as usual, or do I miss something? What happens if you happen to turn left instead of right? The road not taken.
Would the room be different if I was not here? Yes. For one thing I’d turn off the computer, the TV and the lights before I left if I was planning on being out of the room awhile. Dust would be able to settle where I am currently seated in the chair. What about other things, little things and minor details? If I step out of the room is that lucky for me? Is that the very moment the old tree finally gives up the ghost and falls on this half of the house? Or is it unlucky? If I’m out of the room is that when the dust bunnies really start to mess things up?