Gall's Law
Gall’s Law recommends building a working simple system and extending it through testing and feedback. It is a warning about the difficulty of designing many interacting parts at once, not a guarantee that gradual growth succeeds.
THE IDEA
Gall’s Law, associated here with John Gall’s The Systems Bible, states that complex systems that work invariably evolve from simple systems. As a design heuristic, it recommends beginning with something that works and testing additions as complexity grows.
A small working system gives you a baseline. When you add a component or rule, you can examine what changed and whether the parts still work together. An elaborate initial design can make failures harder to isolate.
This is guidance, not proof that every functioning system has the same history. Biological evolution, urban growth, and technological development can illustrate cumulative change, but they follow different processes. A system that becomes more complicated is not necessarily becoming more effective.
When to use it
Software development: Start with a minimum viable product (MVP) and iterate based on feedback, rather than building a feature-complete system from the start.
Business process re-engineering: Trace a convoluted process back to its simple origins to identify unnecessary steps and streamline operations.
Urban planning: Let city services and infrastructure evolve from simple, proven solutions rather than implementing a grand, untested design.
Product design: Develop a simple prototype, test it, and refine, instead of launching a complex final product immediately.
FROM THEORY TO EVERYDAY LIFE
In practice
Bureaucratic Process
A convoluted bureaucratic process in an organization probably began with a simple form that served its purpose, gradually accumulating steps and rules over time.
Biological Evolution
Animals have an evolutionary history involving simpler ancestral organisms. This is an analogy for cumulative change, not evidence that organisms were deliberately designed according to Gall’s Law or descend from bacteria living today.
Urban Development
A town may expand its roads and services as it grows into a city. This illustrates incremental development, though planned cities and major coordinated projects show that urban histories vary.
Technological Progress
A product team starts with a working prototype, adds a feature, and checks how the addition affects the whole. The example illustrates the design heuristic without asserting that a complex technology arose directly from a different invention.
A MOMENT TO REFLECT
Put it to work.
Can you identify a complex system in your personal or professional life that likely evolved from a simple origin?
What can a working simple version reveal before you commit to a more complex design, and what might it fail to test?
How could you apply Gall's Law to simplify a current project or initiative?
References
- The Systems Bible — John Gall
CONTINUE THE CONVERSATION
Source texts
- The Great Mental Models Volume 3 Systems and Mathematics