Thermodynamic Asymmetry of Time and Past Hypothesis for the Early Universe

Based on everyday experience and conventional understanding, there seems to be a difference between the past and the future, which we call the "arrow of time." There are different explanations for the time arrow, one of them is the thermodynamic arrow. However, the fundamental laws of physics, in particular Newton's laws and statistical mechanics, which we expect to explain the phenomenological laws of thermodynamics, do not show the asymmetry. Boltzmann tried to explain the thermodynamic asymmetry by proposing a "past hypothesis" for the early universe. According to this hypothesis, the early universe was in very special initial conditions. But this proposal encountered with many criticisms. While presenting the philosophical dimensions of the "arrow of time" problem and the critiques of the "past hypothesis", we argue that the assumption of a fundamental "time arrow" assumes that the past hypothesis alone is not sufficient to explain it. And there is a need for a more fundamental explanation that may change our view of space-time structure.