The problem: Which one of the presentism and eternalism is the correct picture of the nature of time? Simple Newtonian systems: It doesn't really matter. They are mathematically equivalent, the problem is destined to remain purely philosophical, and there is no way of figuring out the truth, if it exists. Relativistic systems: The presentism becomes problematic, becomes simultaneity isn't absolute anymore. If the presentism was true, we would need to have some inertial frame to be the correct rest frame. The relativity seems to suggest, that the eternalism is the correct answer. Statistical physics: The eternalism becomes problematic. The laws of physics are invariant in time reversal, so there doesn't seem to be any obvious reason for the entropy to increase in some particular direction in an eternal space time. So the statistical physics suggests, that presentism is the correct answer. More about the problem: What I think is mostly puzzling, is that there are physical arguments to the both directions. Is the correct answer, that both of these alternatives is incorrect? What other alternatives are there?