Easily. Many places and times have operated without states but with
legal systems. Law does not require a State, any more than building
roads or delivering mail requires a State.
In medieval Europe, commercial law was entirely developed in private
courts without any power of state based enforcement behind them -- and
yet it worked well, and the Lex Mercatoria is the basis for all modern
commercial law.
In medieval Iceland, there was no "public" law enforcement at all --
all law enforcement was private. And yet, there was law.
If you want to learn more on this topic, I suggest "The Machinery of
Freedom" by Friedman and "The Enterprise of Law" by Benson as good
starting points.
Perry