Write down the 3 principles underpinning Boltzmanns law and indicate which of these is incompatible with the quantum theory of gases 3. The attempt at a solution Well I know two... 1. The conservation of energy 2. Equal probabilities of allowed configurations But I'm a bit stuck with the third. Can anyone help me out here? I know that Boltzmann said that it matters which molecule is in which state and that there is no restriction on the number of molecules that can occupy a given state, but I wasn't aware that this is an underpinning principle. If it is, then I would say that this is the one that isn't compatible with the quantum theory of gases due to the indistinguishability issue.