AMBIGUITY IN THE SECOND LAW OF THERMODYNAMICS

Here is the Kelvin-Planck statement of the second law of thermodynamics:

It is impossible to construct an engine that, operating in a cycle, will produce no effect other than the extraction of heat from a reservoir and the performance of an equivalent amount of work.

"No effect other than the extraction of heat from a reservoir and the performance of an equivalent amount of work" could mean:

(A) At the end of the cycle, both the engine and the surroundings return to the initial state except for the heat disappearance and the result of the work production (e.g. some weight somewhere in the surroundings was initially on the ground but remains lifted after the cycle is over).

(B) At the end of the cycle, both the engine and the surroundings return to the initial state except for the heat disappearance, the result of the work production, AND the unavoidable changes that occur in the body of the OPERATOR - someone or something that assists the process.

It can be shown that, with the interpretation (A), the Kelvin-Planck statement of the second law is true. With the interpretation (B), however, the Kelvin-Planck statement of the second law is false. That is, perpetuum mobile of the second kind IN THE PRESENCE OF AN OPERATOR is possible in principle..

Pentcho Valev