Let's imagine a deterministic universe. A one where quantum mechanics simply doesn't apply. Ok. This was the universe of classical physics. Atoms exist, and they behave deterministically. Fine. Now, how can entropy increase in this universe, altough it has the same laws of physics. In a deterministic universe, the probability of all microstates is not equal, one is 100%, and the others are 0% chance. Since the universe is deterministic, that holds true. So the normal entropy explanation doesn't hold true. Then the question again rises, why does entropy increase and not decrease, if all microstates all not equally likelly?