derivation of wiens displacement law and wiens distribution law from thermodynamic principle.but not from plancks law
This gives the obviously wrong result because of the well-known Rayleigh-Jeans UV catastrophy.
The answer is that we have to consider quantum theory, and this adds the additional universal quantity ##\hbar## of dimension erg s to the game.
So there seems to be no way to get the correct Planck spectrum without quantum theory.
Wien's displacement law, of course, holds for both Wien's and Planck's spectrum.