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Defining a System

Let us examine the concept of system itself. The word has a very broad meaning. Any entity or thing is a system.

All systems have two things in common: (1) they have parts, and (2) the parts interact in an orderly way. Even a gas cloud is a system, because it consists of components (particles) that have a gravitational or electrochemical interaction.

Perhaps a better question would be: what is not a system? Does anything fail to meet the criteria? What about a set of randomly moving particles in space, far apart, not affecting each other in any measurable way?

We could define these particles as a system and give them a label ("a set of particles that do not interact" or "a non-system"). Then, as amorphous and immeasurable as the particles might be, it is a system in our heads.

Of course, when somebody describes a system, we cannot assume the system actually exists, as described, in the outside world. To find out, one must do research, and that is the function of science itself: generating and testing models of natural systems.

There is a procedure for this, the prover­bial scientific method. The heart of it can be summarized very quickly: (1) a model is used to generate non-trivial predic­tions, (2) the predictions are tested, and (3) the model is modified as necessary.

Tests might show that the original model of a system was wrong, or simplistic, or needs modification. If so, the model must be corrected, and this is a routine part of science.

While the model is checked for accuracy, it remains hypothetical. But, in any case, the model itself is a system.

Even if it accurately portrays nothing in the universe, a model is a system. It is a set of related ideas in the cognitive networks of a person.

Non-things can be treated as things and made into a conceptual system merely by labeling them or describing them in words. Consider what happened when linguist Noam Chomsky said certain sentences were meaningless.

Chomsky gave an example of a meaningless sentence: "Colorless green ideas sleep furiously." Chomsky's act gave the sentence a meaning: an example of a non-meaningful sentence.

Chomsky's sentence became a thing. Search the internet for the phrase "colorless green ideas sleep furiously" and a search engine will return tens of thousands of hits.

An attempt at a meaningless sentence has a meta-meaning: a function that can be identified and features that can be identified. It can be labeled ("Chomsky's example of a meaningless sentence") and referenced in a search engine. Similarly, a poorly drawn, fanciful map shows us, if nothing else, an artist's conception of the universe.

Needless to say, physical systems like cars and computers are easiest to understand because we can see or feel their parts, and nobody doubts their reality. But conceptual systems–like rules of different sports, or knowledge of how a library operates, or the delusional system of a schizophrenic–are just as surely systems.

Imaginary systems with no counterpart in the outside world are not necessarily fictitious. Consider the square root of minus 1, the famous imaginary number of mathematics.

The square root of minus 1 is real enough. Mathematicians and engineers use it in calculations, including designing circuits, so imaginary numbers enable computers.

Imaginary or conceptual systems are not unreal. They are just informational in nature, residing in our cognitive networks rather than "out there" in the environment.

The bottom line is that anything perceiv­able or conceivable is a system. It can be a system in the outside world or in somebody's head.

That is a reliable generalization. It can serve as our first system principle, albeit a rather simple and obvious one.

The principle of system definition: Anything perceivable or conceivable is a system.

Write to Dr. Dewey at

Search Psych Web including the General Systems Toolkit and the online textbook Psychology: An Introduction below.

Copyright © 2017 Russ Dewey