Scientists … are trying hard to understand the ways in which structures arise without the imposition of special requirements from the outside. In an astonishing variety of contexts, apparently complex structures or behaviors emerge from systems characterized by very simple rules. These systems are said to be self-organized and their properties are said to be emergent. The grandest example is the universe itself, the full complexity of which emerges from simple rules plus the operation of chance.
Murray Gell-Mann, The Quark and the Jaguar, 100
The Operating System.