Systems Generating Systems

By Christopher Alexander

This is paper written by Christopher Alexander in 1968 about the idea of generating systems, and how we define systems.

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Alexander starts the paper by distinguishing between a "system as a whole" and a "generating system." A system as a whole is not an object, but rather a particular way of looking at an object. A generating system is a kit of parts, with rules about how those parts might be combined.

Precise labeling cuts off exploration

Alexander describes "system" as an imprecise word, but not necessarily in a dismissive way. He says that although your instinct might be to think that it is dangerous for a technical word to lack precision, it is often a helpful characteristic. This perspective seems useful to me—when you make a word precise you are also setting some boundaries that cut short the possibility of exploration: The lack of precision in a label allows ideas to be explored and extended, without them being "cut short by premature definition and precision."

A system is a way of looking at an object

The key definition of a system as a whole is that it is not an object, but a way of looking at an object. For something to be defined as a system there has to be some kind of observed phenomenon that can only be understood as a product of the interaction among the system's parts.

In order to call something a system, you must be able to clearly state:

1. Its holistic behavior
2. The parts within the thing, and the interactions among them, that cause the holistic behavior you have observed
3. How the interaction among the parts actually causes the defined behavior

"System" as a shorthand for not understanding

It's easy to dismiss something as a system when what you really mean is that it's complicated and you don't understand it very well. Alexander seems to imply that people who don't really understand systems tend to label things that they don't understand as "systems." If you want to call something a system in a meaningful way, you need to specify a holistic behavior that you think emerges as a result of some interactions among the system's parts.

Don't underestimate the complexity of a system by applying a simple label to it

If you are observing a complex system you might not be able to successfully abstract the most interesting parts of it because you lack the ability to see the interactions clearly and don't have the right terms for them anyway.

A generating system is a kit of parts

A generating system is a kit of parts with rules about the way the parts may be combined. When you design a generating system you are really designing a system of rules.

Don't design objects

If designers are concerned with creating objects and systems that function as wholes, what we actually need to do is shift the focus from designing objects to designing generating systems. Since generating systems naturally create the necessary holistic properties that make a system a system, that's what we need to design.

To make objects with complex holistic properties, it is necessary to invent generating systems which will generate objects with the required holistic properties.

We become designers of systems which are capable of generating many objects, rather than designers of individual objects.

Reference

Alexander, Christopher. "Systems Generating Systems." Architectural Design 38, no. December 1968 (1968): 605-610.