Gall's Law

A complex system that works has evolved from a simple system that worked. A complex system built from scratch won’t work.

-- John Gall, 1975

Originating in systems design, this law encourages software developers and product managers alike to begin with simple systems and grow towards complexity - rather than beginning with a complex system. This law is often cited as the reason for the failure of complex systems like CORBA, and is hailed as the reason for success of systems which began humbly, such as the World Wide Web.