“The most important work on EA and applied System Theory today.”  “Makes EA more powerful, coherent and usable.”


The systems of interest here are islands of orderly behavior in the ever-unfolding process of the universe.

That does include the solar system, riding a bicycle and the cardio-vascular system.

But the main interest is narrower:

·         Systems in which actors respond to information encoded in messages and memories.

·         Systems in which information describes or directs entities or events of importance to the system’s actors.

·         Human activity systems in which processes depend on messages received and memories retained

·         Computer activity systems in which all the messages and memories are digital.


Business system architects are supposed to observe baseline systems, envisage target systems, and describe both.

So, you might assume they are taught about system theory and systems thinking; but this is far from the case.


Millions of years ago, animals evolved to conceptualise the world in their brains.

Animals also evolved to communicate concepts to each other - well enough.

To cooperate in a social system, animals must communicate by exchanging information.


You can see business systems as formalised social systems.

To cooperate in business processes, system actors must communicate by exchanging information.

They send and receive information in messages and store it in shared memory spaces.

And to succeed in communicating, actors must agree the meanings that are encoded in messages and memory spaces.


In business operations, human activity systems are supported and enabled by computer activity systems.

In the 1970s, business systems were often analysed and designed by people in an Operational Research department.

At the start of the Information Age, many Operational Research departments were absorbed into IT departments.

The PRISM report of 1986 divided the work of business system description into four domains.

The table below positions those four domains in the columns; each divided into three levels.







Infrastructure technology



Business roles & processes,

standardisation, integration

and road maps

Business data

standardisation, integration

and road maps

Business application portfolio

standardisation, integration

and road maps

Platform technology portfolio

standardisation, integration

and road maps



Outline design of a solution’s

required processes

Outline design of a solution’s

data architecture

Outline design of a solution’s

application(s) architecture

Outline design of a solution’s

IT production environment



Detailed design of

processes & use cases

Detailed design of

data stores and flows

Detailed design of

software architecture

Detailed design of

IT production environment


The table positions descriptions of human activity systems to the left, and computer activity systems to the right.

The two kinds of system meet wherever digital data is created and used by humans.


Once systems are described, they can be changed under change control from one generation to the next.

System architects are actors in a meta system that observes, envisages and describes changes to the business systems of an enterprise.

The meta system is sometimes called enterprise architecture.


In 2011, a “systems thinker” asked me what theory underpins enterprise architecture.

He said he couldn’t find any (other than the Zachman Framework - which we agreed was not a satisfactory answer).

I was surprised he didn’t know that general system theory underpins enterprise architecture.

And later, surprised to find how loosely the term "system" is used in much systems thinking discussion.

So, the work introduced here sets out to provide a stronger theoretical foundation for enterprise architecture.


System theory is good to know, good for the soul, and practically useful in all kinds of thinking about systems

Many could benefit from a deeper understanding of it.

Various puzzles are addressed and resolved in this work.

Much is owed to the biologist Charles Darwin and psychologist W Ross Ashby.

The work relates system theory to biology, psychology, sociology and the philosophy of science.


We shall see that social systems thinking emerged in the 19th century.

When general system theory emerged in the 20th century, social system thinkers sought to embrace it.

Later however, some threw off its constraints and set off in a different direction.


Certainly, seeing a business as a social entity is important; and is a primary responsibility of business managers.

The question here is whether classifying a social entity as a "system” has a useful meaning.

If every problem or situation is a system, if everything we name or point to is a system, then the term “system” is meaningless.

This work explores what means to call something (a hurricane, a human being, a society, a business, a radio) a system.

Also, how "general system theory" and "systems thinking" can differ, and even can be contrary to each other.


The work analyses the notions of system theory with reference to theories of description, types, communication and information

The analysis leads towards a coherent and consistent understanding of these matters.

The findings and conclusions can help both authors and users of enterprise architecture standards.

They can help readers detect and resolve ambiguities and contradictions in "systems thinking".

Moreover, they may provide food for thought for philosophers about the description/reality distinction.


Next: read The evolution of thinking.