Further Insight Relative to Cavity Radiation II: Gedanken Experiments and Kirchhoff's Law

Kirchhoff’s law of thermal emission states that cavity radiation must always be black, or normal, irrespective of the nature of the walls. Arbitrary cavity radiation must be solely dependent upon the equilibrium temperature and the frequency of observation. Despite such theoretical claims, it is well established that laboratory blackbodies are not constructed from arbitrary materials, but rather from n early perfect absorbers of radiation over the frequency of interest. In the laboratory , arbitrary cavities do not contain black radiation. This experimental fact stands in direct conflict with Kirchhoff’s formulation. Nonetheless, Kirchhoff’s law of thermal emission endures, in part, due to Gedanken experiments whose errors in logic are difficult to ascertain. In this work, thought experiments are discussed in order to expose some logical shortcomings. It will be demonstrated that Kirchhoff’s law cannot be supported in this context