may observe a different order for the same events. It is not necessary to apply any concept of time to an energy change or a movement in space occurring in objective reality. However Ut can be used to translate Universal potential energy change i.e.change in 4th dimensional position to a position in time, so long as it is recognised that every object and particle experiences its own version of Universal time, according to its movements within 4 dimensional space.Any vertical difference in position between object is also a difference in 4th dimensional position i.e.difference in Universal potential energy. Time is an abstract collection of mental concepts that allow the mind to interpret experience within subjective reality, not a physical fundamental parameter or process. I put litte stock in either of these ideas. I prefer to avoid metaphysical ideas as much as possible. Tegmark's idea might indeed be the case, but there is no way we could ever test it. As such I think it is scientifically worthless. It is something worth talking about over scotch and cigars. :-) Mathematics studies self-consistent structures. If you at all take the pulse of mathematics it is clear that mathematical systems multiply a lot faster than physics does --- and I mean a lot faster. It is hard to know how all of these systems can ever be wrapped into a physical theory of everything. BTW, I hate the term Theory of Everything (TOE), it presumes too much. There are two types of bad