  The second law of thermodynamics is asymmetric with respect to time as it
says that the entropy of the universe must have been lower in the past and will
be higher in the future. How this time-asymmetric law arises from the
time-symmetric equations of motion has been the subject of extensive discussion
in the scientific literature. The currently accepted resolution of the problem
is to assume that the universe began in a low entropy state for an unknown
reason. But the probability of this happening by chance is exceedingly small,
if all microstates are assigned equal a-priori probabilities. In this paper, I
explore another possible explanation, which is that our observations of the
time-asymmetric increase of entropy could simply be the result of the way we
assign a-priori probabilities differently to past and future events.

Statistical Mechanics