Take a building, for example. Physics dictate that over time it will be worn down by the elements, eventually being unrecognizable from its original state as the entropy increases. This process cannot be reversed without altering the very state of the object and through that we prove that not only does everything strive towards high entropy, time also moves in a linear, forward motion. Kind of like an arrow that loses speed and height the further it goes.
Of course, time itself is relative but when we're talking about the second law of thermodynamics this is the approach we need to take.