A Critique on Caratheodory Principle of the Second Law of Thermodynamics
  Caratheodory's axiomatic formulation of the second law is considered as one of the standard forms of formulation of the law. However, it was mired in advanced mathematics. The formulation was strongly criticized by Max Planck, for it was based on the analysis of adiabatic processes and adiabatic accessibility. A thermodynamic process is said to be possible only if it satisfies both first law and the second law. A process is said to violate the second law only when it satisfies the first law, and violate the second law. We show here that violation of Caratheodory principle of the second law violates the first law itself. In other words, adiabatic inaccessibility arises only as a consequence of violation of the first law. This we demonstrate by assuming, in contradiction to Caratheodory's principle, that the states considered adiabatically inaccessible as adiabatically accessible, and prove that the assumption leads to no paradox - thereby showing that the adiabatic inaccessibility arises as a result of violation of the first law. 
Radhakrishnamurty Padyala
physics.gen-ph