Ben-Naim in three articles dismissed and “answered” the Levinthal’s paradox. He announces there are pitfalls caused by the “misinterpretation” of thermodynamic hypothesis. He claims no existence of Gibbs free energy formula where the variable is a protein’s conformation X . His Gibbs energy functional is G(T, P, N, P(R)), where the variable is probability distributions P (R) of the conformations. His “minimum distribution P_eq” is wrong. By carefully establishing thermodynamic systems, we demonstrate how to apply quantum statistics to derive Gibbs free energy formula G(X). The formula of the folding force is given.