   Puzzle question
  As they say, does a tree make a sound when there is no one around to hear it?Well, I believe that it does make a sound, but my question is that when you look at an object in the real world, and you only see certain parts of it, and not the other parts that compose it, then is the other parts really there. Meaning, is glEnable(GL_CULLFACE) on?   
  Is this a real programming question or is it just a philosophical question? Face culling is used to remove (or rather, not render) one side of a polygon. It does not mean it culls any part that is not in view.   ;  The "backfacing" of a polygon does not exist in the real world. So no, there is no culling. However, in 3D graphics there really is no concept of area. A tree would be solid in the real world while you only see the external surface area in a graphics application.I am curious about XTAL256's question as well: Is this a real programming question or is it just a philosophical question?   ;  The real world is comprised of voxels in a non-rectangular grid.   ;  Easy to solve. Place a mic + recorder, record, leave the tree. If there is sound on the tape, the tree makes sound.As for culling, everything the player does not need to see (can't see) is not rendered. It's still there- as data in memory, for example.   ;  I think you first have to define exactly what 'exists' mean. Usually we say something exists since we can detect it in some way. So if there is a tree in the forest (with or without sound :-) ) but we do not sense it in some way then we can say nothing about whether it exists or not. As long as, if we sense it, again, the state is consistent with how it should have been with all natural laws applied in the time between.I believe there was an article on new scientist a while ago about how a particle only got a certain state after it was measured and everything became consistent with it even in the past. But after the measurement was done it was fixed.