Infodynamics, Information Entropy and the Second Law of Thermodynamics

Information and Energy are related. The Second Law of Thermodynamics, which states that entropy continuously increases, applies to changes in energy and heat, but it does not apply to information dynamics. Changes in energy and information are coupled but have completely different dynamics. Infodynamics has made clear that Thermodynamic Entropy and Information Entropy are distinct concepts. Total Energy contains Free Energy and Thermodynamic Entropy, whereas Total Information or Information Entropy contains Useful Information and Noise, both of which may be gained or lost in irreversible processes. Increases in Free Energy of open systems require more Useful Information, reducing or increasing Thermodynamic Entropy. Empirical data show that the more Free Energy is created, the more Useful Information is required; and the more Useful Information is produced, the more Free Energy is spent. The Energy–Information relationship underlies all processes where novel structures, forms, and systems emerge. Although science cannot predict the structure of information that will produce Free Energy, engineers have been successful in finding Useful Information that increases Free Energy. Here, I explore the fate of information in irreversible processes and its relation to the Second Law of Thermodynamics, showing that distinguishing between Thermodynamic Entropy and Information Entropy, and disentangling its interactions, is fundamental in advancing our understanding of the thermodynamics of irreversible processes.