Abstract
The aim of this paper is to analyze time-asymmetric quantum mechanics with respect to
the problems of irreversibility and of time’s arrow. We begin with arguing that both problems
are conceptually different. Then, we show that, contrary to a common opinion, the
theory’s ability to describe irreversible quantum processes is not a consequence of the
semigroup evolution laws expressing the non-time-reversal invariance of the theory.
Finally, we argue that time-asymmetric quantum mechanics, either in Prigogine’s version
or in Bohm’s version, does not solve the problem of the arrow of time because it does not
supply a substantial and theoretically founded criterion for distinguishing between the two
directions of time.