Life is the self-regulating conversion of thermodynamic disequilibria into directed motion.
Year: 2021
Type: preprint
Abstract: Life is traditionally defined by a long list of properties, but classifying structures as living or non-living would require a single recognizable difference. Of the many conceptual difficulties and philosophical insights surrounding a theory and definition of life, perhaps the most pertinent is that we may not yet have an adequate system or periodic table with which to delineate this difference. However, recent empirical evidence shows that a range of biological molecules, including ribozymes and enzymes with rotating or ratcheting subunits, undergo repetitive conformation state changes driven by thermal agitation and energy exchanges, in turn governing catalysis of reactions fundamental to metabolism and replication. These molecules exhibit disparate structures, but share the principle of repetitive unidirectional conformation changes driven by thermodynamic gradients, producing directional motion. Here, life is defined as a self-regulating process whereby matter undergoes cyclic, unidirectional conformation state changes that convert thermal agitation and excitation into directed motion, performing work that locally reduces entropy. By extension, a living thing is a structure comprising, at least in part, an autonomous network of units operating on the heat engine principle. The principle of self-regulating networks of heat engines is independent of any specific chemical environment or molecular structure; this definition should apply universally across biospheres characterized by differing biochemistries.
Source: arXiv (Cornell University)
Author: Simon Pierce
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3195976248