Determinism (and hysteresis)

Copyright 2016 Graham Berrisford. One of about 300 papers at Last updated 14/07/2017 12:08


This paper contains thought related to determinism.


Terminology. 1

Determinism.. 2

Determinism in biology and business. 3

Determinism in EA.. 4

Indeterministic/probabilistic systems. 5

Free will 6

Conclusions and remarks. 7



Activity systems perform behaviors and change state.

State: the current values of an entity’s variable properties.

Process: one or more state changes over time, or the logic that determines which state changes lead to which other state changes.

Hysteresis: the process by which the system’s information state can be derived by replaying all events that have so far cross the system boundary.

Deterministic: the quality of a system that means its next state is predictable from its current state and input event.

Stochastic: the quality of a system that means its next or future state is not predictable, and appears random.


In this and related papers:

·         Orderly or deterministic <is contrasted with> random or fuzzy, probabilistic or stochastic.

·         Linear change or outcome <is contrasted with> non-linear or chaotic change or outcome.

·         Adapting (changing variable values) <is contrasted with> evolving (changing variable types or rules).


This two-dimensional taxonomy of theories contrasts deterministic and probabilistic theories.

Theories of the universe


Discrete (quantum leaps)



Digital system modelling


Social systems thinking?

Quantum Mechanics


Given a deterministic system you can predict how an actor or system will respond to a discrete event.

Providing that is, you know enough of its current state or memory and the rules it applies when responding to events.


An actor responds to a particular input event in:

·         conventional determinism: by following rules that refer to its current state.

·         hysteresis: by following rules that refer to past input events.


So, to predict an actor’s next output, you must know not only its rules, but also its current state or past event history.


Hoare Triples

A Hoare Triple specifies a deterministic process in a formal logic statement of the kind {P} S {Q}.

This means:

·         IF the precondition (P) is true

·         WHEN an event is detected and the process (S) terminates successfully,

·         THEN the post condition (Q) will be true afterwards.


The precondition refers to the state of the system (or its memory of past events) when the new event is detected.

The post condition refers to the state of the system after the system has responded to the event.


Service-oriented (stimulus-response) specification of business systems is discussed in other papers.

It is important to note that architects need logical service contracts to be extended with measurable non-functional requirements.


Deterministic machines

A deterministic machine is an entity that performs deterministic processes.

Honey bees, motor cars, human games and businesses can all be described as deterministic machines.

IF (Preconditions)

WHEN (Event)

AND (Process completes)

THEN (Post conditions)

A football is in play

The ball crosses a side line

A player takes a throw in

The football is in play again

A taxi journey is in progress

The destination is reached

The driver collects payment

The taxi is available for hire.

Your hair needs cutting

And you have money

You sit in the barber’s chair

The barber washes and cuts your hair

You have shorter hair

Money has been transferred from you to barber

The barber's scissors have worn down a little.

An applicant is > 18 years old

An application is made

The application is approved

Application state = accepted

Determinism in biology and business

In “Design for a Brain” W Ross Ashby treated the brain as a deterministic machine.

The quotes below are taken from chapter 2 and appendix 1.


Ashby “Our starting point is the idea, much more than a century old, that a machine, in given conditions and at a given internal state, always goes to a particular state.”

Ashby took the view that the responses of the human brain to its senses are state-determined.

Many business operations are similarly state-determined.

When a payment has reached its due date, the enterprise will invoice a customer for the amount due.


Ashby: “We take as basic the assumption that an organism is mechanistic in nature.”

Ashby considered the human brain as deterministic system.

(This is a theoretical position, since we cannot know the internal state or processes of a human well enough to predict the choices it will make.)

Business operations are often defined as deterministic systems.


Ashby: “From whatever position they have initially, they go towards a state of equilibrium.”

A homeostatic system reaches stability by maintaining variables within acceptable limits.

A business does not strive to reach a state of equilibrium in the way a biological entity does.

But it does strive to avoid states in which it goes out of business or business rules are broken.

And it strives to meet measurable business objectives, which (being SMART) are expressed as target variable values.


Ashby: “A variable is a measurable quantity that has a value.”

To monitor or direct a system’s behaviour, the observer must identify suitable variables.

Business variables may include an employee’s salary, a customer’s credit balance, and a supplier’s average delivery duration.


Ashby: “The state of the system is the set of values that the variables have.”

A system’s behaviour is determined by the state variables the system holds and updates.

A business holds state variables values in databases of (e.g.) employees, products, orders, customers and suppliers.

The enterprise is seen as collection of control systems connected to business operations by feedback loops.

The control systems monitor and direct entities (employees, customers, suppliers) in the performance of business operations.

They monitor the state of those entities and activities by collecting information messages.

They direct those external entities or activities (or try to) by sending them messages.


Ashby: “A system is any set of variables which he [observer] selects from those available on the real machine.”

An observer’s system description is, necessarily, a selective abstraction from the reality of business operations.

A system description is abstract, it describes core processes and variables, but cannot fully represent business operations.

An architecture description is necessarily a selective abstraction from the reality of business operations.

Determinism in EA

To paraphrase Ashby: Enterprise architects deal with all kinds of business process that are regular, or determinate and reproducible.

Determinate means the responses of a business (to events and service requests) are determined by business rules applied to system state or memory.


To facilitate the transactions of government and commerce, EA formalises inter-actor communication and behaviour.

Not only is the representation of information in messages and memories standardised using data types (defined in data models).

But also, the behaviour of actors is standardised using business rules (defined in data and/or process specifications).


EA frameworks assume business systems behave according to presumptions distilled in the UML 2.1 standard.

·         “all behavior in a modeled system is ultimately caused by actions executed by so-called “active objects

·         “behavioral semantics only deal with event-driven, or discrete, behaviors” 


Clearly, a business must respond to discrete events and service requests.

Many responses are determined by applying business rules to the current state of the business and/or its memory of past events.

And in formalising a social system, the memory must be independent of any individual human.


Service-oriented (stimulus-response) specification of business systems is discussed in other papers.

It is important to note that architects need logical service contracts to be extended with measurable non-functional requirements.

Indeterministic/probabilistic systems

The opposite of determinism is the view that events are not caused deterministically by prior events.

It appears in quantum mechanics and in philosophical discussions of free will


The Copenhagen interpretation is an informal collection of attempts to express the mathematical formalism of quantum mechanics.

Presumption: the results of experiments must be reported in ordinary language (not in arcane terms, using names or clusters of mathematical symbols).


Postulate of the quantum

Subatomic events are only perceptible as indeterministic physically discontinuous [discrete] transitions between discrete stationary states.

A transition is called a quantum leap.

No event is certain; the entire outcome of anything is unpredictable except as a probability.

Various consequences are inferred from this postulate.


Heisenberg's uncertainty principle

Generally: incompatible conjugate properties cannot be measured with arbitrary precision at the same time.

Specifically: the more precisely the position of some particle is determined, the less precisely its momentum can be known, and vice versa


The Copenhagen interpretation also attempts to reconcile the apparent dualism of "wave" and "particle" in a fashion suitable to human understanding.

Free will

There are three broad positions on free will

The first two below are incompatibilist; meaning that free will is incompatible with determinism


Metaphysical libertarianism

Metaphysical libertarians claim that determinism is false and therefore free will is possible.


Hard determinism

Hard determinists claim that determinism is true and therefore free will is impossible.

A biologist may say attributing free will to a person is ego-centric or species-centric.

It is merely the way we interpret abilities and behaviours that have developed through biological evolution.

We are nothing but vehicles constructed by our genes to reproduce themselves.

Socio-cultural systems thinker Boulding wrote that humans act according to input messages and remembered mental images.

In other words, a person’s actions are deterministic, based on their internal state.


Are humans and social groups deterministic?

There seems to be no convincing way, no logic or test, to answer the question

Certainly, a human actor’s current state includes a memory of past events, and this influences its decisions.

But you cannot inspect or measure an actor’s current state or past history

Nor can you know the rules it applies to making decisions in response to events or conditions.


Note: a hard deterministic system can produce unpredictable or unexpected outcomes in the long term.

Also, all human societies and laws assume sane people make choices of their own free will.

It would be impossible to live in a human society without assuming the same.

And so, the only practical position seems to be compatiblism.



Compatibilists conceives free will to be compatible with determinism.

They consider the debate between libertarians (free will) and hard determinists (determinism) to be a false dilemma.

Contemporary compatibilists identify free will as a psychological capacity, such as to direct one's behavior in a way responsive to reason.

Conclusions and remarks

To paraphrase Ashby: Enterprise architects deal with all kinds of business process that are regular, or determinate and reproducible.

Determinate means the responses of a system (to events and service requests) are determined by rules applied to system state or memory.

If a process cannot be described in this way, then it lies outside the scope of the operational systems designed and governed by architects.


When applying system theory, Ashby and Boulding assumed people’s actions are deterministic, based on their internal state.

However, there is an anti-determinism streak in much socio-cultural systems thinking.


Socio-cultural systems thinkers often seek to differentiate human activity systems from deterministic systems.

They do this by characterising human systems as “complex”, “adaptive”, “non-linear”, “indeterminate” “chaotic” etc.

However, the use of these terms in opposition to deterministic is questionable.


The question about business systems that employ human actors is not whether humans behave deterministically or not.

Suppose for the sake of argument that humans are indeed deterministic machines; there are three questions


Q1) Is a human’s machine merely a subsystem of the business machine?

No! The former exists independently of the latter, it is more complex, and its rules may be different.


Q2) Can a deterministic human actor disregard the rules of the business system, or act outside them?

Yes! They often choose to follow their own rules.


Q3) Do business managers want to capitalise on the natural abilities of the human machines?

Often, yes. Human actors may be encouraged step outside the operational system

They may step up to a meta system in which they analyse and change the roles of the operational system.

This is a principle of “agile development” methods discussed in other papers.



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