Gall's Law (Working Complex Systems Evolve from Simple Ones)

John Gall's principle that complex systems that work invariably evolved from simple systems that worked. The corollary: complex systems designed from scratch never work and cannot be patched into working—you have to start over with a working simple system. This isn't pessimism about design; it's an empirical observation about how complexity must be built. The internet evolved from ARPANET; successful companies evolved from simple MVPs; effective organizations evolved from small, functional teams. Attempting to design full complexity upfront reliably produces systems that fail in unpredictable ways.

When to use it

When planning complex system builds and tempted to design everything upfront; when complex systems are failing and the instinct is to add more complexity; when evaluating whether to pursue incremental evolution or revolutionary redesign; when managing software, organizational, or product development projects.

How it can help

When building anything complex—products, organizations, processes, systems—start with the simplest version that works, then add complexity incrementally, testing at each stage. Never attempt a 'big bang' launch of a fully complex system. The discipline: if you can't make a simple version work, no amount of additional complexity will help—complexity hides problems, it doesn't solve them. For organizational design: don't redesign the entire org chart at once; make one structural change, observe its effects, then make the next.