We discuss the importance of the CP (simultaneous particle-antiparticle and
left-right permutation) and T (time reversal) symmetries in the context of
fundamental interactions. We show that they may provide clues to go beyond the
4-D gauge interactions. We insist on the fact that T violation is not
associated to a degradation (like in entropy), but simply characterized by
different trajectories.Comment: This is a "basic" introduction (non-technical) aimed at showing the
importance of CP violation wrt gauge theorie