I posted another topic here which died and this question was never answered: In ancap law theory, what defines a proportional response?
EDIT: Sorry, should have been more clear: A proportional response to someone who has aggressed against you. It is intuitively appealing enough that someone who has stolen $100 from me should be made to return my $100, but how can it be defined for all cases? If a man who has no children murders one of mine, how should he be forced to compensate?
It is not a satisfying answer to put it up the courts, because the perpetrator doesn’t get to decide which court he goes to, and what if the court gives an unjust, unproportional response?