Entropy Grows from Coarse-Grained Understanding

The early universe exhibits limited microstates leading to the increase of entropy over time as systems evolve into macrostates with greater microstates. This increase in entropy is fundamentally related to the arrow of time, which is not apparent in classical deterministic physics assuming knowledge of the microstate. However, since absolute knowledge of the universe's microstate is unattainable, observers can only interact with the universe through consistent macroscopic information that reflects strong correlations across different observers. Thus, the understanding of entropy and the arrow of time is rooted in our observational limitations rather than a clear deterministic framework.