"Have you ever wondered if the light really does go off when you
shut the fridge door and no one can see it? How could you tell?
Perhaps you could rig up a remote camera. But then what
happens when you turn the camera off? What about a tree
falling in a forest where no one can hear it? Does it really make
a noise? How do you know your bedroom continues to exist
unobserved when you aren’t in it? Perhaps it vanishes every
time you go out. You could ask someone else to check for you.
The difficult question is: does it carry on existing when nobody
is observing it? It’s not clear how you could answer these ques-
tions. Most of us think that objects do continue to exist unob-
served because that is the simplest explanation. Most of us too
believe that the world we observe is out there somewhere: it
doesn’t just exist in our minds."