ABSTRACT
Statistical Mechanics has a lofty goal. It aims at explaining complex natural phenomena by building up the theory from a few basic postulates or assumptions. For example, given interaction potential between the constituent atoms and molecules, we can predict the behavior of the system. This is indeed a formidable task that requires a sophisticated theoretical approach. It is fair to say that SM has indeed largely fulfilled its ambitious goal in a variety of areas across natural sciences and can be regarded as an established discipline equipped to handle complex situations. Such an approach was developed essentially by Boltzmann and Gibbs (and still being developed), starting from two postulates, connected by a hypothesis. They together form the backbone of the theory. 28Here we discuss these two postulates and the hypothesis. The postulates themselves involve somewhat abstract concepts of phase space, trajectory, and ensembles. It is important to clearly understand both the concepts and the postulates. Therefore, we first introduce these concepts; follow them by discussion of the postulates mentioned above.
