Understanding the Development of the Concept of Entropy through the Context of the Operation of Maxwell’s Demon

Maxwell’s demon was proposed by James Clerk Maxwell in 1867 as a thought experiment. The demon started as a friend whose aim was to help us understand the statistical character of the Second Law of Thermodynamics and, as time progressed, it became a “paradox” that definitely had to be solved. As a result, this thought experiment has occupied the mind of many researchers for over 130 years. Throughout these analyses—not only of the original demon of Maxwell, but also of all the demon’s descendants that followed—it can be clearly illustrated that the demon has an intimate symbiotic relationship with the concept of entropy. The fundamental legacy of this relationship is the connections that exist first, between entropy and information, and second, between thermodynamics, statistical mechanics, the theory of information, the theory of computation, and quantum mechanics. In this paper we trace the lengthy history of the cooperation between Maxwell’s demon and entropy. Furthermore, we assess the current status of entropy in the context of the operation of the demon. In addition, throughout our discussion, we aim to illustrate the possible function of Maxwell’s thought experiment as a methodological tool to explain entropy’s development.