Do we need law for order? Order comes first. People keep promises, settle disputes and deal with cheats long before anyone writes a statute, and they keep doing it where no statute reaches. What holds a community together is the standards its members expect of one another, written or not. Written law is one way of recording and enforcing those standards. It is not their source. The question that matters is less whether a rule is written down than who enforces it, and whether they can be held to it.
Because there are many paths to order, a stateless world would not be one society with one code. It would be at least as varied as the world already is, between nations and between regions within them.
This section takes up three questions: natural law (are there rules nobody made?), positive law (what makes a made rule binding?), and law without a state (how disputes get settled when no one holds a monopoly on settling them).
Further reading
Bruce L. Benson, The Enterprise of Law: justice without the state (Pacific Research Institute, 1990). The standard economic case for law produced outside the state.
Mapping Police Violence. Data on killings by police in the US.
“The Criminal Legal System for Radicals” (Strangers in a Tangled Wilderness).
“Why the rule of law suffers when we have too many laws” (The Volokh Conspiracy, Reason, 2017).