Towards a Hierarchical Definition of Life, the Organism, and Death

Abstract

Despite hundreds of definitions, no consensus exists on a definition of life or on the closely related and problematic definitions of the organism and death. These problems retard practical and theoretical development in, for example, exobiology, artificial life, biology and evolution. This paper suggests improving this situation by basing definitions on a theory of a generalized particle hierarchy. This theory uses the common denominator of the "operator" for a unified ranking of both particles and organisms, from elementary particles to animals with brains. Accordingly, this ranking is called "the operator hierarchy". This hierarchy allows life to be defined as: matter with the configuration of an operator, and that possesses a complexity equal to, or even higher than the cellular operator. Living is then synonymous with the dynamics of such operators and the word organism refers to a select group of operators that fit the definition of life. The minimum condition defining an organism is its existence as an operator, construction thus being more essential than metabolism, growth or reproduction. In the operator hierarchy, every organism is associated with a specific closure, for example, the nucleus in eukaryotes. This allows death to be defined as: the state in which an organism has lost its closure following irreversible deterioration of its organization. The generality of the operator hierarchy also offers a context to discuss "life as we do not know it". The paper ends with testing the definition's practical value with a range of examples.

Galactic distribution of chirality sources of organic molecules

“…There are also fruitful adventures to be had looking at heredity-first or membranefirst scenarios, or scenarios that have some features of these three, e.g. the infra-biological units of Szathmery [47], or the dual-closure concept of Jagers op Akkerhuis [48].…”

Finding or Creating a Living Organism? Past and Future Thought Experiments in Astrobiology Applied to Artificial Intelligence

“…Recall that systems may be open or closed depending on how their boundaries are defined and whether energy can cross that boundary. Jagers (2010; and Jagers and van Straalen (1999) define two additional closures. With functional closure, the functional elements of systems must comprise a mathematically closed set; and with structural closure, there must be a structure that physically encloses the object (mathematically: topological closure) for a thing to qualify as an operator.…”

“…In the process of understanding these four contexts, the reader will see that an idea of emergent properties of systems will be a consistent thread, with recourse to a theme: large-scale characteristics arising from small-scale processes (Schrödinger, 1944). Along the way, there will also be an introduction to Jagers' operator theory, which posits that dual closure, of both functional and structural elements, is the building block of a class of systems called operators, and these culminate in living organisms (Jagers op Akkerhuis, 2010).…”

What is life?

“…Although this definition is more comprehensive than the previous ones and includes a reference to thermodynamics, in my opinion it has four drawbacks: (i) the term “self-sufficient” is not adequate because the quality of life does not provide self-sufficiency; (ii) the thermodynamic component does not highlight how fundamental low entropy or high order is for any living being; (iii) information can be acquired from “within” and not only from the environment; (iv) life is not a system is a process and living beings are the system where that process occurs (I discuss this point below). From a very different perspective it was defined life as “matter with the configuration of an operator, and that possesses a complexity equal to, or even higher than the cellular operator” [ 18 ]. This proposal introduces a new term, the operator, which is somewhat confusing, excludes viruses and makes a strange classification of living systems.…”