I had a couple of interesting thoughts today on the matter of Many Worlds. First is that, in a way, I think the so-called "branching" posited for MWI could be thought of as a derivative of time. For example, time is the derivative of space (i.e. using change in space with respect to time)... then branching is kind of exponential (infinite?) change with respect to both space and time. I can't think of a good way to represent this idea other than to say if space-time is a square, then space-time-branching is a cube. Or perhaps, branching is "every" space-time that's possible. Which brings the next idea... that if this branching is indeed occurring, then that would force time to move forward only. My reasoning is that with each quantum moment, these branches continue "expanding" and branching more. Let's suppose that I decide to go back in time... I can't unless "me" in all of the associated branches also decide to go back in time. Because "me" has logically consistent choices that involve not going back in time, we know that some of them won't. Therefore, none of them actually could. Therefore, time can only go forward. The only exception would be if there were some way to eliminate the logical possibility of moving forward in time, which would force time to either stop, or move backward. The other, slight, possibility is that you could move backward in time, but that it would be imperceptible as the movement would be "complete" in that it would reverse all memories, knowledge, and information - as if you had never moved forward in time.