A classic example is the New York Stock Exchange, which was created as a location at which stocks could be bought and sold Monday to Friday from 9 a.m. to 4 p.m. No overriding authority set prices, volume limits, etc. These were established by pockets of people who pursued their own preferences in a manner resembling chaos. In yelling out on the floor that he was willing to buy ABC stock at X price, a trader intended to pursue nothing more than the preferences of his client. But an unintended consequence of his action was the establishment of an overall price for ABC stock.
Spontaneous order can resemble chaos.
Ironically, this resemblance to chaos may indicate an aspect of why spontaneous order is efficient. After all, the shifting circumstances to which this sort of order responds have no logical or predictable order. Just as the trading floor of a stock exchange cannot be run according to Miss Manners' rules of etiquette, so too does a dynamic society require institutions with fluidity. Indeed, the main advantage of a decentralized system of decision-making may well be its ability to adjust constantly and quickly to shifting circumstances. Where social engineering demands a stable future and a godlike knowledge of the present, spontaneous order recognizes and embodies the inevitability of change and the inadequacy of human knowledge.