I came across a discussion about the nature of time and whether or not time is an illusion on a physics forum. I'm not so much interested in the philosophical issues regarding time, but the following, which is more related to physics, is something that confuses me:
Is our world a three dimensional world that keeps changing or is it a four dimensional world that remains static?
Relativity seems to say that the world is actually a four dimensional static object, because it is difficult to imagine how the world could be a three dimensional changing world in a spacetime where simultaneity is relative.
On the other hand, statistical mechanics does seem to imply that the world is a three dimensional changing world because entropy increases. The laws of physics are invariant under time reflection, so if the world is a four dimensional static one, why should an arbitrary solution to the laws of physics be the kind of solution were entropy increases in 1 direction of time? I once read somewhere is has something to do with the initial conditions of our universe. This clears things up a little but I'm still confused.