Since humanity began to comprehend abstract concepts, time has remained one of the most complex mysteries. We can remember, experience, and predict, but we have never experienced the reverse flow of time — broken glass does not restore itself, people do not become younger, and yesterday does not return. This phenomenon is called the "arrow of time."
Nevertheless, physicists, while exploring the equations governing fundamental particles, such as the equations of classical mechanics and quantum theory, often find that they are valid for both the forward and reverse flow of time. Why then is our perception of time so unambiguously directed?
The most common explanation is related to thermodynamics. In the 19th century, Ludwig Boltzmann established a connection between the arrow of time and the concept of entropy, which describes the level of disorder in a system. According to the second law of thermodynamics, entropy in a closed system increases over time, which explains processes such as the melting of ice or the decay of complex systems.
Although entropy provides an understanding of the irreversibility of many processes, it is not a definitive explanation for the one-way flow of time. The fundamental microscopic laws still allow for the movement of time in both directions. Scientists from Hainan University have proposed a new theoretical concept that sheds light on this issue, as reported by SCMP.
The proposed theory focuses on the quantum level. Researchers argue that the direction of time may arise from the internal evolution of quantum systems. At this level, systems constantly interact, exchange information, and become correlated. As these correlations accumulate, the evolution of the system becomes nearly irreversible, despite the theoretical possibility of reverse time flow.
Thus, the irreversibility of time is not something external. It arises from the structure and dynamics of the system. When quantum components interact, information about their past states is lost, creating a natural perception of time as "before" and "after."
This new approach does not refute either thermodynamics or the general theory of relativity; rather, it complements them. Entropy remains important at large scales, while the theory of relativity explains the behavior of time under conditions of high speeds and strong gravitational fields. The proposed concept also helps bridge the gap between microscopic laws and macroscopic experience.
The philosophical paradox known as the "memory argument" asserts that we cannot reliably remember our thoughts from the past, as their meaning changes with language and context. Researcher Jay Richardson offers an alternative view based on cognitive science data, showing that memory is not an archive but an active process of reconstruction.
