  This work reviews the understanding of the direction of time introduced by
Hans Reichenbach, including the fundamental relation of the perceived flow of
time to the second law of thermodynamics (i.e. the Boltzmann time hypothesis),
and the principle of parallelism of entropy increase. An example of a mixing
process with quantum effects, which is advanced here in conjunction with
Reichenbach's ideas, indicates the existence of a presently unknown mechanism
that reflects global conditions prevailing in the universe and enacts the
direction of time locally (i.e. the "time primer"). The possibility of
experimental detection of the time primer is also discussed: if the time primer
is CPT-invariant, its detection may be possible in high-energy experiments
under the current level of technology.
