I was studying the Statistical mechanics and what I have understood is that if there is a large number of particles in a system , and if we want to study the system then we have to calculate the position and momentum of all particles in every instant of time, and this will be the complete information about the system , but this is impossible to do . So in statistical mechanics people use the total no. Of microstate $\Omega$ to calculate the thermodynamic veriables.
But my question is that how can I argue that to calculate the thermodynamic veriables we only need the no. Of microstate not the detailed information about those microstate state ( information about those microstate state means say the position and momentum at every insrant)?
We actually have Boltzmann hypothesis $S=k_B ln(\Omega)$ which tells that entropy is fully related to only no. Of microstate not to the full details of those microstate.
But this is a hypothesis we can not explicitly prove this. But I want a proper explanation that why I need only the no. Of microstate not the detailed information about those microstate.