  It is a remarkable fact that all processes occurring in the observable
Universe are irreversible, whereas the equations in which the laws of physics
are formulated are invariant under time reversal. The emergency of
irreversibility from the fundamental laws has been a topic of consideration by
physicists, astronomers and philosophers since Boltzmann's formulation of the
"H" theorem. In this paper I shall discuss several aspects of this problem and
its connection with the dynamics of space-time, within the framework of modern
cosmology. I shall comment, briefly, on the nature of physical time and its
relation with the so-called "consciousness".
