What are Systems?

A system (physical or conceptual) is a set of "bounded" properties.

What is a System?

A system is any “bound”, finite, set of physical and/or conceptual properties (elements) such as physical objects, rules, or space time coordinates.

Simply, if we take any real or conceptual objects or concepts, interacting or not interacting, and define a boundary (if we put them in a metaphorical container), we have a system (everything in the container is a system).

For example, a flock of birds is a system, the core ruleset that makes birds flock is a system, a betting strategy for blackjack is a system, the universe is a system, and the lack of organization on my desk is a system of sorts too.

Systems can be open or closed, be a mix of real or conceptual elements, have interacting elements or not, be simple or complex, and include subsystems or not. As long as it is a bounded set of elements, it is a system.

TIP: Given there is different types of infinities a finite set can technically contain “smaller” infinities.

TIP: Mass-energy in a closed system can’t be created or destroyed. Statements like this are why we need to understand systems.

Modeling Systems and Systems Thinking

By modeling the interaction of elements in physical and conceptual systems we can better understand both a system’s individual parts, and how those parts work together. Thinking of the universe in terms of its real and conceptual systems is called systems thinking. See Systems Thinking at Wiki.

Since everything in the universe can be modeled as a simple or complex system, systems thinking is not surprisingly fundamental to physics, computer science, social science, mathematics, and other complex sciences.

TIP: Systems theory, or systems thinking, is the study of systems. Complexity science is the field of science that studies complex and simple systems. On this page we cover the basics of how systems and their “elements” work. Learn more about systems in general.

How Do Systems Work?

We can use the word system in abroad way to describe any elements that exist in relation to each other, but typically when we say “system”, we are referring to the modeling and study of a groups of somehow interconnected elements.

A System isn’t Itself “a Thing”

Anything can be modeled as “a system” (either simple or complex, open or closed, with interacting or not interaction parts), with this in mind, a system itself isn’t “a thing”. Rather a system can only be defined by its properties (elements), the relationship between its properties, and it’s relationship to other systems. We can analyze complex systems to better understand how systems work in general.

This video looks at sets and systems in detail. I highly recommend the Complexity Academy series on systems theory.

Basic Systems Theory Definition

  • Systems have two key aspects: a boundary (like a membrane) which contains the “bounded” finite set of properties inside the system, and an environment which is everything outside the system.
  • There are also two main types of systems: physical systems (a system of real objects, like an atom or flock of birds) and conceptual systems (a systems of ideas or non-physical objects) .
  • System can also be simple or complex. If we think of the universe as a complex system we can say all systems within it are simpler systems. So to understand the universe we may start by trying to model elementary particles and forces.
  • We can look at systems in two ways, analysis (reducing a system to its parts / properties / elements) and synthesis (seeing how the parts work together, and studying the affects between systems). Essentially, with systems thinking, the relationship between parts are equally as important as the parts themselves.
  • When we look at sets of elements they are either interacting, or non-interacting. We can break sets of systems down into subsystems.

All systems can be modeled (if not the system as a whole, it’s parts), and rule-sets can be devised for all systems. All complex systems can be reduced to simpler interactions of properties to better understand the larger system. All systems can be explained and defined by language (including math, code, graphics, spoken language, and written language).

What Is A System.

What does Bounded mean? Bound or bounded means a finite set. So simply, not infinite. All systems are “bound”, but “bound” systems can be open or closed to outside input (more on that below).

What is a system? A more philosophical look at systems from the Schumacher Institute.

Physical Systems

There are physical systems, which are contents bound to the system (typically by the forces or chemical reactions). The contents of a system are called properties of a system, everything outside the system is the environment. In physics specifically, a physical system is a portion of the physical universe chosen for analysis.

Modeling Physical Systems, An Overview.

Conceptual Systems

Conceptual systems work roughly the same way, but are more conceptual by nature and thus can have a network of ideas rather than physical properties. In loose terms a system could be steps to winning a video game. All the steps are contained (bound) within the system.

Conceptual System Boundary Example 1.

Open Systems Versus Closed Systems

Systems can be open to outside input, or closed. An open system can let “bound” contents out and accept new contents in. This model below explains a basic open system.

Basic open system model.

This chart shows an open physical system. Conceptual systems can be modeled in this way as well.

Simple Systems Versus Complex Systems

A simple system is a system with only a few properties that can be connected together. Complex systems are larger systems with more moving parts. It can be near impossible to figure out a complex system, but by modeling sub-systems (and finding patterns) we can get a better understanding of complex systems. We can also study how systems interconnect and how similar properties arise between systems.

The Properties of a System

A system is not itself “a thing.” It is a holding of  “shared properties.” For instance, at the smallest levels of matter, a photon can only be described by its properties; we cannot find a tangible photon to that holds these properties. You can also think of a cell. We have a membrane, nucleus, organelles, and cytoplasm, but if we ask “what is all that affixed to,” we only find smaller bits of elements, molecules, atoms, and ultimately photons again.

For something like a tabletop card game, a system is a set of rules and pieces that are “legal” within the “bounds” of a given game. It’s still a collection of properties, but the nature of a conceptual system means we have to be broader when we form physical systems.

Regardless of the system type, we can say that systems are collections of properties; all properties are rooted in the same universal laws, and thus all systems are analogous. See our page on the theory that “all systems are analogous here”.

Systems & Subsystems, Basic Facts. NASAconnect explains, a system is only a collection of it’s parts.


A system is a set of bounded properties. That means a system, conceptual or not, open or closed, is simply a finite collection of properties.



"A System is a Set of Properties" is tagged with: Collective Intelligence, Complexity Science, Cooperation, Infinity, Systems

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