The physical character of information

• Published in: Proceedings of the Royal Society. A, Mathematical, physical, and engineering sciences Vol. 465; no. 2107; pp. 2155 - 2175
• Main Authors: Karnani, Mahesh, Pääkkönen, Kimmo, Annila, Arto
• Format: Journal Article
• Language: English
• Published: London The Royal Society 08-07-2009
• Subjects: Communication; Communication systems; Data models; Energy; Energy Transduction; Entropy; Evolution; Flux density; Free Energy; Information processing; Information representations; Natural Selection; Thermodynamics
• ISSN: 1364-5021; 1471-2946
• DOI: 10.1098/rspa.2009.0063

The mathematical theory of communication defines information in syntax without reference to its physical representation and semantic significance. However, in an everyday context, information is tied to its representation and its content is valued. The dichotomy between the formal definition and the practical perception of information is examined by the second law of thermodynamics that was recently formulated as an equation of motion. Thermodynamic entropy shows that the physical representation of information is not inconsequential in generation, transmission and processing of information. According to the principle of increasing entropy, communication by dissipative transformations is a natural process among many other evolutionary phenomena that level energy-density differences between components of a communication system and its surroundings. In addition, information-guided processes direct down along descents on free energy landscapes. The non-integrable equation for irreversible processes reveals that there is no universal analytical algorithm to match source to channel. Noise infiltration is also regarded by the second law as an inevitable consequence of energy transduction between a communication system and its surroundings. Communication is invariably associated with misunderstanding because mechanisms and means of information processing at the receiver differ from those at the sender. The significance of information is ascribed to the increase in thermodynamic entropy in the receiver system that results from execution of the received message.