Temperature calculation for solids and liquids.

Hi all

Do we always use the formula
KE = 3/2*RT
to calculate temperature!? What is the rationale in using the same in the case of liquids and solids!? Since R is universal GAS constant!


Besides, do not be fooled by names as they usually have very limited interpretation, i.e., historical issues, personal egos, humorous moments…
After so many years of science I would certainly take a large pause before calling any physical theory/constant “universal” any longer.