Claudio Borghi (Liceo Scientifico Belfiore di Mantova)
In this paper I would like to put forward a broad critical analysis of the concept of time in physics. With regard to relativistic time, founded on the clock hypothesis explicitly formulated in recent works by Tim Maudlin and David Malament, I propose a new interpretation of clock effect as a gravitational and pseudo gravitational effect, and I remark that only some real clocks measure durations in agreement with the predictions of general relativity. I focus on the probable disagreement between the measurements obtained through radioactive and atomic clocks. I discuss Carlo Rovelli’s ideas about the possibility of disregarding time in the formulation of classical, relativistic and quantum mechanics, and I explore the physical meaning of his hypothesis of thermal time. I argue that the fundamental physical theories describe different levels of physical reality, namely quantum, relativistic and thermodynamic ones, and therefore they give different operational definitions of time. I stress that thermal time cannot be reduced to relativistic time and, in the conclusive sections, I explicitly claim that different times are generated inside the different clocks employed for measuring durations. This hypothesis opens the possibility of a new foundation of the theory of physical time, and new perspectives in theoretical and philosophical researches.