Abstract
This paper proposes a critical synthesis about different theories of time in
physics and a new interpretation of its operational reality. We built it on two,
deeply analyzed, fundamental ideas: the mathematical nature of Newtonian and
relativistic time and the consequent need to build physical theories of time
starting from the measurements obtained by real clocks. We observe that
relativistic theories refer to axiomatic assumptions about clocks, probably not
verified by experiments if we use clocks of different construction. We propose
the concept of evolutionary internal time and we conclude that a new
interpretation of the nature of physical time should arise from a deep and
accurate reflection about the rate of clocks. We believe that this approach to the
question could open new theoretical perspectives about the evolution of physical
systems.