Information as Physical Selection of States

This conceptual essay proposes a physical definition of information as the selection of possible states of a system rather than as a code, message, or symbol. Using prebiotic systems and membrane physics as a foundation, it argues that information emerges when physical constraints restrict the space of accessible internal processes. In early protocellular systems lacking genes, enzymes, and signaling pathways, amphiphilic membranes acted as the primary regulatory structures by filtering environmental fluctuations through state-dependent properties such as fluidity, permeability, and stability. Modern cells retain this state-based informational layer, although it is largely obscured by complex biochemical regulation. This framework provides a coherent physical and evolutionary basis for understanding the origin of biological information prior to symbolic encoding.