Accepting this, it is possible to calculate the macroscopic behavior of the gas without knowing the details of the motion of each particle.
In other words, the macroscopic behavior of a system does not depend on the particular ensemble used for its description.
A general objective is to provide quantitative relations between the measurable (and hopefully controllable) features of the materials' micro-scale structure and its macroscopic mechanical behavior.
A relevant operator is needed to describe the macroscopic behaviour of the system; an irrelevant observable is not.
Essentially, the act of random collision events results in a macroscopic behavior that is not random at all.
Temperature is sometimes used as an example of an emergent macroscopic behaviour.
Convection in a liquid or gas is another example of emergent macroscopic behaviour that makes sense only when considering differentials of temperature.
The properties and interactions of these mesoscopic structures may determine the macroscopic behavior of the material.
These materials usually gain their properties from structure rather than composition, using the inclusion of small inhomogeneities to enact effective macroscopic behavior.
Small spatial inhomogeneities create an effective macroscopic behaviour, leading to properties not readily found in nature.