 This raises the question of how the two ways of looking at the gas fit together. Since neither the thermodynamic nor the mechanical approach is in any way privileged, both have to lead to the same conclusions. Statistical mechanics is the discipline that addresses this task. From a more abstract point of view we can therefore also say that SM is the study of the connection between micro-physics and macro-physics: it aims to account for a system’s macro behaviour in terms of the dynamical laws governing its microscopic constituents. The term ‘statistical’ in its name is owed to the fact that, as we will see, a mechanical explanation can only be given if we also introduce probabilistic elements into the theory.