We simply want to have an unambiguous number. An additive constant would not matter for analysing processes, whereas a multiplicative constant does. We want to make contact with thermodynamics: E = TS-PV+μN, so there's not too much freedom.
Thanks. Another explanation came to my mind. At thermal equilibrium the entropy is at the maximum value and therefore it stays at Heisenbergs lowest possible value; DpDx=h. @@josthijssen6782
@@josthijssen6782 Thank you for the explanation. I see, a constant wouldn't matter. Especially not in differences between states. It came also to my mind that at thermal equilibrium the entropy is at a maximum. This brings Heisenberg's relation to its minimum possible value Dx.Dp=h.
