Gall's Law
A working complex system invariably evolved from a working simple one.
John Gall, 1975. Complex systems designed from scratch don't work. The successful complex systems we use today all started as simple ones and evolved through use. Trying to design the complex version upfront produces a non-working complex system.
The principle is brutal for ambitious engineers and product designers. The instinct is to design the full sophisticated version. Gall's Law says: that version won't work. Build the simplest working version first. Let it evolve.
For operators, this is the philosophical foundation of MVP, lean startup, and iterative development. Most failed grand product launches are violations of Gall's Law.
Examples in the wild
Most large platform launches that try to be everything from day one fail. The platforms that succeed (AWS, Stripe, Slack) started focused and evolved into platforms once the simple version worked.
Conglomerate businesses built by acquisition rarely outperform organic businesses built around a core. The 'design the complex thing upfront' violates Gall's Law at the business architecture level.
Most successful personal habits started simple (10 minutes of exercise) and grew. Trying to install a complex routine all at once usually fails by week two.
Gall's Law is one of the mental models we apply through real cases inside the Pareto MBA — a part-time program for professionals who want to think clearly about business.