The directionality of time, from past to present to future, is a fundamental aspect of our perception and the laws of physics. This concept is deeply rooted in the arrow of time, which is related to the increase of entropy.
Entropy is a measure of disorder or randomness in a system. The second law of thermodynamics states that the total entropy of an isolated system tends to increase over time. When events unfold in a way that increases entropy, they are consistent with the forward flow of time.
If time were to flow backward, entropy would need to decrease, going against the natural tendency defined by the laws of thermodynamics. This contradicts our everyday observations and experiences.
While the microscopic laws of physics are time-symmetric (meaning they don't inherently distinguish between past and future), the macroscopic world exhibits an arrow of time due to phenomena like entropy increase. This directional flow of time is a crucial aspect of our understanding of the universe. The specific reasons for the asymmetry of time, however, are still a topic of philosophical and scientific exploration.