[I]magine that you have never seen or heard of a roller rink. Nor an ice-skating rink. Long ago people didn’t know anything of skating. Imagine yourself one of them. Imagine that a friend walks up to you and tells you with great enthusiasm about his new idea for a business: “I’ll build a huge arena with a smooth hard wooden floor and around the perimeter a naked iron hand-rail. I’ll invite people to come down to the arena and strap wheels onto their feet and skate round n’ round the arena floor. They won’t be equipped with helmets, shoulder-pads, or knee-pads. I won’t test their skating competence, nor separate skaters into lanes. Speedsters will intermingle with toddlers and grandparents, all together they will just skate just as they please. They’ll have great fun. And they’ll pay me richly for it!”

There’s a good chance that your friend wouldn’t be optimistic. Far too dangerous, he might say. Perhaps the only way it could work is if we hired someone really smart and ethical to run it. Of course, that would be a misunderstanding of spontaneous order, as Dan Klein explains in this interesting essay. Jane Jacobs also appreciated the concept of unplanned order:

Jacobs believed the most organic and healthy communities are diverse, messy and arise out of spontaneous order, not from a scheme that tries to dictate how people should live and how neighborhoods should look.

More here.