Where does complex phenomenon come from?

Most people believe complex phenomenon requires a complex origin.
(Yes, that's an assumption.)

The common belief is that a complex phenomenon implies a designer (an old argument for the existence of God). But very complex systems are based on simple rules. Physics is replete with examples, such as gravity controlling everyday objects and distant galaxies. Economics has the "invisible hand" law. Natural Selection is well accepted in biology. Medicine has revealed how life depends on one molecule, DNA.

Another common mis-perception is that change is linear. From the simple rules, change can be exponential. From the emergence of a small start, growth can be rapid as the rules lead to repeated doublings.

On a societal level the spontaneous emergence of an phenomenon will proceed like biological event. Both are undesigned and unplanned. Both need resources to maintain and grow. Both result in unintended consequences. Both change their environment and intermingle with the old structures.

The hardest task is to recognize which social phenomena are dangerous before the threaten.