Entities and how they change

In defining terms, it is common to over-generalize. If we say a spade is a tool, that is true, but doesn’t distinguish spades from other kinds of tool.

Many definitions of a "system" are extremely generic. If we say a system is a thing composed of related parts, we should distinguish it from other things divisible into parts. If we say a system is a perspective we take of a thing in reality, we should distinguish it from other perspectives we may take (after all, every description is a perspective).

• "Common definitions of a system do not enable us to distinguish things that are systems from things that are not." (Salado and Kulharni, at the 31st Annual INCOSE Symposium, July 2021).

The first version of the ISO 42010 standard - on principles for describing systems - did not define a system. It left the choice of system theory to the reader. The current version now speaks more generally of describing an "entity of interest".

To be going on with, suppose a system is an entity of interest. What is entity? In our sensations and descriptions of the world, we discretize it. In verbal language, we divide the world into things of two kinds - things that persist (objects or entities), and things that happen (processes or events).

This article focuses on entity thinking (about structures that persist), including how entities are created, how they change, from one state to the next, and how they change from one generation to the next. It returns to systems thinking at the end.

Contents: Reality, description and truth. Taking a structural view of entities. Time as state change. The life history of an entity. How do systems differ from entities?

Reality, description and truth

As a follower of Kant might say: we observers cannot know things in the world (noumena) directly; we can only know what we sense or perceive (phenomena) of things, and the representations and descriptions we make of them.

However, to interpret this as meaning our view of the world is entirely personal and subjective is misleading. Having represented a thing we observe in the form of a sensation in our nervous system, we can compare that sensation with already-registered sensations of past entities (like for like). If we recognize the entity, then respond to it, manipulate it or predict its behavior successfully, we demonstrate - empirically - that our internal representations of phenomena correspond, well enough, to the noumena "out there".

If this was not true, we could not succeed in recognizing a friend, tying our shoelaces, or hitting a tennis ball. Moreover, we humans can share representations of things by translating them into words that symbolize or signify things we observe. We can describe a thing to others by

• likening it to another thing, drawing a simile, as when saying Mars is like the Earth

• classifying it in more general terms, as we do when we say Mars is a “red” “planet”.

As the philosopher A J Ayer wrote: “In [a sentence] describing a situation, one is not merely ‘registering’ a sense-content; one is classifying it in some way or other, and this means going beyond what is immediately given.”

If the receiver of a message we send succeeds in recognizing, manipulating, or predicting the behavior an entity we describe, then we can reasonably conclude the description does correspond, well enough, to a shared reality. In other words, senders and receivers of the message share the same understanding of the types they use to classify entities.

• “[If two people are capable of understanding one another] it follows that each of us, although his sense-experiences are private to himself, has good reason to believe that he and other conscious beings inhabit a common world.” (“Language truth and logic” A J Ayer.)

The more successful we are at sharing a description (such as Newton's F = M * A) and using it, the more reason we have to believe that the description we share does correspond to reality well enough to be trusted and useful, and may be called "objective" or true".

We can also describe entities we envisage. It might be a thing to be built, such as a garden shed. Or it might forever remain a fantasy, such as a unicorn, which we imagine has much the same attributes as a horse.

Taking a structural view of entities

Space and time are continuous in every direction. To describe reality, we discretize it. We divide the ever-unfolding process of the universe into more or less discrete entities.

Initially, we may simply identify that there is "something out there". And as followers of Wittgenstein might conclude, the boundary we draw around it may be fuzzy. However, nature gives us a hand in the form of phase boundaries that separate solid structures from the space that surrounds them. For example, we see fishes in the sea, plants and animals in the atmosphere, and bodies in outer space as distinct entities.

We commonly name and describe an entity regardless of behaviors it performs or participates in. For example, we observe Mars to be a discrete and stateful structure that has attributes such as mass, diameter, distance from the sun, and colors.

Marrs does also have behaviors, but in everyday discussion, we speak of their structural products (dust clouds, volcanoes, polar ice caps and canyons) rather than the processes that produce them.

The following terms and concepts are used in describing an entity.

Name: an identifier, a symbol that uniquely identifies an entity.

Entity: a structure that we observe or envisage to be discrete and stateful, and may name or point to within a wider environment or domain interest.

Discrete: locatable in space and time, separate from what is outside it, before it and after it.

Stateful: has a structure we see as persisting over the time period of interest to us.

State: the structural features or attributes of an entity. The current values of a system’s state variables. For example, the state of an ecology is represented by predator and prey populations. The state of a tennis match is presented by game, set and match scores. The state the entities and events that a business monitors and directs is represented in one or more databases. The state of a system changes, under its own internal drive and/or in response to inputs.

Microstate: the state of a entity's atomic parts, their values or quantities (such as the mass of one organism).

Macrostate: the state of aggregate entiry-level properties (such as total biomass).

The idea of micro and macro states implies an entity is described at two levels: one whole composed of atomic parts (think of molecules in a gas cloud, or people in a society). When describing a large enttity we may define it at several levels of granularity, by composition and decomposition.

Invariant: an attribute whose value does not change over the time period of interest to us.

Variable: an attribute whose value changes over time. Variables can include quantitaive amounts (such as populations and weights), qualitative attributes (such as colours and addresses), stages in a life history (such as egg, maggot and fly), and compound variables or complex types - structures that relate two or more atomic variables.

Hysteresis: the idea that a system’s current state derives from its history. The state of the system today depends on the state that past events have left it in. (In software systems, the current state can be generated by replaying past events.)

Part: a component of an entity that can be described as an entity in its own right.

However, for some thinkers, behaviors come before structures, and we should think also of how a thing changes over time.

Time as state change

• “The only constant in life is change”. Heraclitus.

Physicists see time's arrow as the direction that moves the universe from

• a low entropy and highly clumped energy state, to

• a high entropy and continuous distributed energy state (in which nothing of interest happens).

In between the beginning and end of time, complex structures emerge - including life forms able to reproduce themselves, and even describe themselves. This article is about this middle age of the universe, in which we (life forms) detect and describe entities as structures in space that change over time.

In cosmology: if there was a big bang, there was no time before it, because time requires space. Entities cannot move or change unless there is space from them to be in and change in. To measure time is to measure state changes in entities we observe in space.

In thermodynamics: the second law (entropy increases) tells us to that to arrange entities in a pattern requires the input of energy. Ashby wrote that in the cybernetic view of systems (see below), a sufficient supply of energy is normally taken for granted.

In quantum physics: a 2022 paper suggested quantum systems (or single particles) can move both forward and backward in time. However, if time were to flow backward at the much higher level of life forms, we humans could not detect or describe it, since our thinking would be reversed and our memories erased.

In psychology: as Albert Einstein said, time is an illusion that moves relative to an observer. The physicist Julian Barbour wrote a book on the illusion of time, saying change is real, but time is not; it is only a reflection of change. To observe state changes in the world (such as the hands of a clock moving) is to experience parallel state changes in the brain. As time flows forward, our brains consume energy to lay down memories of entities we have observed,

Our psychological impression of how fast time passes is another matter. In a period when changes happen in close succession, time appears to pass quickly. In a period when no change is happening, time appears to pass slowly. But paradoxically, in retrospect, the former period is remembered as substantial, and the latter is not remembered.

The life history of an entity

Since an entity exists in space and time, it can viewed as both

• A thing in space (object, entity, structure or form) and as

• A thing that changes over time (process, behavior or function).

Which comes first, entities or events, objects or processes? Physicists see objects as side effects of the processes of the universe. Evolutionary biologists see organisms as a transient processes, within the ongoing process of life. Even "object-oriented" programmers start with what Bertrand Meyer called higher level processes, and Ivar Jacobsen called use cases, then design a structure in which objects (of whatever size and scope they choose) interact to complete the required processes.

To fully understand what a persistent entity is, we must to think about its life history. How does it emerge from the ever-unfolding process of the universe? How does it change state over time? How far can it change, yet still remain the same entity? How doe it die? What kind or degree of change makes an entity into a different entity?

The emergence of an entity

Aside: the term "instantiate" is ambiguous, it can mean either "display" or "create". We may say that an entity instantiates (displays) the features of a type; or say an entity or process instantiates (creates) an entity.

The life of an entity starts when it is instantiated by a process. An entity may be created by a process of

• evolution (be it inorganic or organic), or

• manufacture: (by a life form, or a machine created by one.)

An entity may be manufactured by

• copying another entity (cf. a simile),

• instantiating a generic class or type (cf. a metaphor), or

• following a recipe to manufacture it

To manufacture a cake requires a manufacturer/baker, to perform a process/baking by following a recipe. Biological evolution works by incrementally changing the DNA/recipe that each new generation of an entity uses to manufacture itself.

Two kinds of change in the life of a entity

Having emerged, an entity may circle around states (like a traffic light or a planet) and/or advance (like a moon rocket) until it dies. And during its life, an entity may change in various ways, notably:

State change: a change to a variable value (such as cooler or hotter), which may happen under a system's internal drive, or in response to an input.

Evolution or mutation: a change that adds or removes variables or behavior types, whether organically or by design.

Either kind of change may be called an adaptation if it helps an entity to survive in a changing environment, or meet some aims.

The replacement of a entity

Replacement: During its life time, one entity may yield space to a new version or generation of that entity.

The death of a entity

Death: An entity may die from the exhaustion of a resource it depends on, the decay or removal of its parts, random destruction by an external force, or deliberate intervention by an external agent.

A entity's continuity of existence

Although every attribute of an entity may change over time, what makes it "an entity" to us is continuity of existence. And for observers, continuity of identity is important. What I call my grandfather's axe is still the same axe to me, even though its handle and blade have been replaced.

In biology, the coherence of a biological organism over time lies in the continuity of the DNA structure its existence depends on.

In sociology, what matters is continuity of name. We see IBM as an entity, though it has changed radically over decades from a hardware manufacturer to a service provider. My local soccer club has moved and changed over 150 years, yet I think of it as the same entity.

Continuity of identity is a highly subjective way to define what an entity is. Can we be more objective about how to define what a system is? How far can a system change, yet still remain the same system? What kind or degree of change makes it into a different system? These questions are addressed in later articles.

How do systems differ from entities?

Mars is an entity. Is it also a system? People do view systems as structures or entities that persist. And much of what has been said in this article about an entity may be said also of a system. However, if every entity is a system, and vice-versa, then "system thinking" adds no value to everyday entity thinking.

At this point we must be clear what a “system” is. Our first impulse is to point at an entity and say “that is the system". However, every entity of interest has countless describable variables. We cannot describe all of them, and we never try to. Rather we select the relatively few variables of an entity that are relevant to some interest already given, and we look for a pattern in how those variables change value, in how the entity behaves.

As Peter Checkland (a soft systems thinker) told us, a system is a particular way of looking at an entity in the world. It is a pattern in how structures interact over time to produce a result of interest. It is a transient island of orderly or regular behavior, carved out of the infinite complexity and ever-unfolding process of the universe.

As Ashby (a cybernetican) told us, a system is a way of behaving, a pattern of behavior in which structures are engaged, like a hurricane or a football match.

System: a set of elements (variables or parts), related to some given interest, that interact in a particular pattern of behavior to change or advance the system's state.

Behavior: rules that govern state changes, perhaps wrt invariants.

When describing a simple object (such as a pendulum or thermostat), we may say the entity and system are associated 1-1. The object is designed to perform or participate in one particular process.

By contrast, when studying a large and complex entity, we may observe several distinct patterns of behavior - distinct systems. Mars has an atmosphere that behaves as a weather system. In the past it had water on the surface and a system of evaporation and condensation. Its volcanoes have filled up with lava and exploded. And Mars participates in the solar system.

Until an entity is described as manifesting the features of a described system, to call it a "system" has no particular meaning. And if one entity manifests the features of several different described systems, then to call it a system is ambiguous - until we say which system we are talking about.

Related articles

This is the 1st of five related articles

• Entity thinking

• System theories

• System theories and EA

• Seven systems thinking principles

• Applying system theory to social entities

If you want to read these articles in the context of a book, watch this space.