Living systems are by definition open self-organizing systems that have the special characteristics of life and interact with their environment. This takes place by means of information and material-energy exchanges. Living systems can be as simple as a single cell or as complex as a supranational organization such as the European Economic Community. Regardless of their complexity, they each depend upon the same essential twenty subsystems (or processes) in order to survive and to continue the propagation of their species or types beyond a single generation..
Miller said that systems exist at eight "nested" hierarchical levels: cell, organ, organism, group, organization, community, society, and supranational system. At each level, a system invariably comprises 20 critical subsystems, which process matter/ energy or information except for the first two, which process both matter/energy and information: reproducer & boundary.
The processors of matter/energy are:
The processors of information are
His central thesis is that the systems in existence at all eight levels are open systems composed of 20 critical subsystems that process inputs, throughputs, and outputs of various forms of matter/energy and information. Two of these subsystems—reproducer and boundary—process both matter/energy and information. Eight of them process only matter/energy. The other 10 process information only.
All nature is a continuum. The endless complexity of life is organized into patterns which repeat themselves—theme and variations—at each level of system. These similarities and differences are proper concerns for science. From the ceaseless streaming of protoplasm to the many-vectored activities of supranational systems, there are continuous flows through living systems as they maintain their highly organized steady states.''Seppänen (1998) says that Miller applied general systems theory on a broad scale to describe all aspects of living systems”
Miller says the concepts of space, time, matter, energy, and information are essential to his theory because the living systems exist in space and are made of matter and energy organized by information. Miller’s theory of living systems employs two sorts of spaces: physical or geographical space, and conceptual or abstracted spaces. Time is the fundamental “fourth dimension” of the physical space-time continuum/spiral. Matter is anything that has mass and occupies physical space. Mass and energy are equivalent as one can be converted into the other. Information refers to the degrees of freedom that exist in a given situation to choose among signals, symbols, messages, or patterns to be transmitted.
Other relevant concepts are system, structure, process, type, level, echelon, suprasystem, subsystem, transmissions, and steady state. A system can be conceptual, concrete or abstracted. The structure of a system is the arrangement of the subsystems and their components in three-dimensional space at any point of time. Process, which can be reversible or irreversible, refers to change over time of matter/energy or information in a system. Type defines living systems with similar characteristics. Level is the position in a hierarchy of systems. Many complex living systems, at various levels, are organized into two or more echelons. The suprasystem of any living system is the next higher system in which it is a subsystem or component. The totality of all the structures in a system which carry out a particular process is a subsystem. Transmissions are inputs and outputs in concrete systems. Because living systems are open systems, with continually altering fluxes of matter/energy and information, many of their equilibria are dynamic—situations identified as steady states or flux equilibria.
Miller identifies the comparable matter-energy and information processing critical subsystems. Elaborating on the eight hierarchical levels, he defines society, which constitutes the seventh hierarchy, as “a large, living, concrete system with [community] and lower levels of living systems as subsystems and components”. Society may include small, primitive, totipotential communities; ancient city-states, and kingdoms; as well as modern nation-states and empires that are not supranational systems. Miller provides general descriptions of each of the subsystems that fit all eight levels.
A supranational system, in Miller’s view, “is composed of two or more societies, some or all of whose processes are under the control of a decider that is superordinate to their highest echelons” . However, he contends that no supranational system with all its 20 subsystems under control of its decider exists today. The absence of a supranational decider precludes the existence of a concrete supranational system. Miller says that studying a supranational system is problematical because its subsystems
...tend to consist of few components besides the decoder. These systems do little matter-energy processing. The power of component societies [nations] today is almost always greater than the power of supranational deciders. Traditionally, theory at this level has been based upon intuition and study of history rather than data collection. Some quantitative research is now being done, and construction of global-system models and simulations is currently burgeoning.
At the supranational system level, Miller’s emphasis is on international organizations, associations, and groups comprising representatives of societies (nation-states). Miller identifies the subsystems at this level to suit this emphasis. Thus, for example, the reproducer is “any multipurpose supranational system which creates a single purpose supranational organization” (p. 914); and the boundary is the “supranational forces, usually located on or near supranational borders, which defend, guard, or police them” (p. 914).
Bailey says that LST, perhaps the “most integrative” social systems theory, has made many more contributions that may be easily overlooked, such as: providing a detailed analysis of types of systems; making a distinction between concrete and abstracted systems; discussion of physical space and time; placing emphasis on information processing; providing an analysis of entropy; recognition of totipotential systems, and partipotential systems; providing an innovative approach to the structure-process issue; and introducing the concept of joint subsystem—a subsystem that belongs to two systems simultaneously; of dispersal—lateral, outward, upward, and downward; of inclusion—inclusion of something from the environment that is not part of the system; of artifact—an animal-made or human-made inclusion; of adjustment process, which combats stress in a system; and of critical subsystems, which carry out processes that all living systems need to survive.
LST’s analysis of the 20 interacting subsystems, Bailey adds, clearly distinguishing between matter/energy processing and information-processing, as well as LST’s analysis of the eight interrelated system levels, enables us to understand how social systems are linked to biological systems. LST also analyzes the irregularities or “organizational pathologies” of systems functioning (e.g., system stress and strain, feedback irregularities, information-input overload). It explicates the role of entropy in social research while it equates negentropy with information and order. It emphasizes both structure and process, as well as their interrelations