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What Is 'Gall's Law'?

Gall's Law states that all complex systems that work evolved from simpler systems that worked. If you want to build a complex system that works, build a simpler system first, and then improve it over time.

Josh Kaufman Explains 'Gall's Law'

Here’s a weekend project for you: build a car from scratch. No pre-manufactured parts or plans allowed. Just a block of metal, a few simple tools, your knowledge, and your imagination. How do you think your project will turn out?

Even if the project takes a year, chances are it will be a complete disaster — if your car works at all, it’ll be far less efficient and reliable than even the worst car from a commercial manufacturer.

Now imagine building a modern computer, creating a cure for cancer, or cloning a human being from scratch. Inevitably, you’ll suffer through a series of expensive and demoralizing failures.

Why is it so hard to build working complex systems from scratch? John Gall, one of the first major complex systems theorists, provided the answer.

Here’s Gall’s Law: all complex systems that work evolved from simpler systems that worked. Complex systems are full of variables and Interdependencies that must be arranged just right in order to function. Complex systems designed from scratch will never work in the real world, since they haven’t been subject to environmental selection forces while being designed.

Uncertainty ensures you will never be able to anticipate all of these interdependencies and variables in advance, so a complex system built from scratch will continually fail in all sorts of unexpected ways.

Gall’s Law is where environmental Selection Tests meet systems design. If you want to build a system that works, the best approach is to build a simple system that meets the environment’s current selection tests first, then improve it over time. Over time, you’ll build a complex system that works.

Gall’s Law is why Prototyping and Iteration work so well as a value-creation methodology. Instead of building a complex system from scratch, building a prototype is much easier—it’s the simplest possible creation that will help you verify that your system meets critical selection tests.

Expanding that prototype into a Minimum Viable Offer allows you to validate your Critical Assumptions, resulting in the simplest possible system that can succeed with actual purchasers.

Iteration and Incremental Augmentation, over time, will produce extremely complex systems that actually work, even as the environment changes.

If you want to build a system that works from scratch, violate Gall’s Law at your peril.

Questions About 'Gall's Law'

• Are you trying to build a complex system from scratch?
• Could you start with a simpler system that already works, then build upon it?

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"A complex system that works is invariably found to have evolved from a simple system that worked. The inverse proposition also appears to be true: a complex system designed from scratch never works and cannot be made to work. You have to start over, beginning with a simple system."

John Gall, systems theorist

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